From knosack@park.uvsc.edu (Kris Nosack)
Newsgroups: comp.lang.basic.visual.announce
Subject: FAQ: (3/95) comp.lang.basic.visual.* VB/Win Frequently Asked Questions
Date: 23 Jul 1995 07:10:38 -0000

Posted-By: auto-faq 3.1.1.2
Archive-name: visual-basic-faq/windows

Last-modified: 12.03.95


                       VISUAL BASIC FOR WINDOWS (VB/Win)
                      Frequently asked Questions & Answers
                                 Section IX - B


   The following symbols indicates new & updated topics:

   [++] means topic is updated in this issue
   [**] means topic is new in this issue

   Hope this makes it easier for Our Regular Readers   ;-)



   TABLE OF CONTENTS:
   ******************


   A. PREFACE [++]

          1. About this document

          2. Where to get the VB/Win FAQ

          3. Kudos & comments


   B. GENERAL VISUAL BASIC QUESTIONS

          1. Does VB/Win make standalone .EXE files?

          2. What is the current version of Visual Basic for Windows?

          3. Where can I get updated VB and other Microsoft files?

          4. Help! I am lost on ftp.microsoft.com.

          5. Where can I get good up-to-date information about VB?  [++]

          6. Are there any examples of commercial applications built using
              Visual Basic? [++]

          7. Limits of VB? [**]


   C. COMMON VISUAL BASIC PROGRAMMING QUESTIONS

          1. What's the difference between MODAL and MODELESS forms?

          2. When/Why should I use Option Explicit?

          3. Why does everybody say I should save in TEXT not BINARY?

          4. Is the Variant type slower than using other variable types?

          5. How do I make a text box not beep but do something else when I
              hit the Enter key?

          6. How do I implement an incremental search in
              list/dir/combo/file boxes?

          7. How do I get the Tab key to be treated like a normal
              character?

          8. How do I make an animated icon for my program?

          9. What is passing by reference?

          10. I get a "file not found" error on the IIF function when I
              distribute by program. Uh?

          11. Is there any way to pass a variable to a form apart from
              using global variables? [++]

          12. How should dates be implemented so they work with other
              language and country formats?

          13. Can a VB application be an OLE server?

          14. How do I dial a phone number without using the MSCOMM VBX?

          15. I have [several] megabytes of memory. Why do I get an "out of
              memory" error?

          16. How do I mimic a toggle button? [++]

          17. How do I get my application on top?

          18. Is there a way to break long lines in VB code?

          19. How do I remove/change the picture property of a control at
              design time?

          20. Is a [foo] VBX/DLL available as shareware/freeware?

          21. How do I make my applications screen-resolution independent?

          22. How do I do Peek and Poke?

          23. Why doesn't "my string" & Chr$(13) do what I want?

          24. How do I prevent multiple instances of my program?

          25. How do I implement an accelerator key for a text box?

          26. How do I force a file dialogue box to reread the currect
              disk?

          27. How do I get the number of free bytes on a disk? [**]

          28. Data Control missing from toolbox when I use VB under NT 3.5.
              Huh? [**]


   D. ADVANCED VISUAL BASIC PROGRAMMING ISSUES

          1. How do I tell when an application executed using the SHELL
              command is finished?

          2. How do I access C style strings?

          3. How can I change the printer Windows uses in code without
             using the print common dialog? How can I change orientation? [++]

          4. Any tips for speeding up VB?

          5. How do I speed up control property access?

          6. How much gain in performance will I get if I write my number
             crunching routines in C instead of Visual Basic?

          7. How do you make a TEXTBOX read only? Or, how do I prevent the
             user from changing the text in a TEXTBOX?

          8. How can I create a VBX?

          9. How do you change the system menu (on the Control-Menu Box)?

          10. How do I play MID, WAV or other multimedia files?

          11. How can I call a 'hidden' DOS program from VB?

          12. How do I do drag & drop between applications?

          13. How do I use GetPrivateProfileString to read from INI files?

          14. How do I implement Undo?

          15. How do I create a window with a small title bar as in a
              floating toolbar? [++]

          16. What is Pseudocode?

          17. Does VB support pointers to functions?

          18. How do I program the Novell NetWare API from VB?

          19. Some Visual Basic 4 rumours

          20. How do you change the icon and otherwise manipulate the DOS
              box? [**]

          21. How do I make the mouse cursor invisible/visible? [**]

          22. How do I create controls dynamically (at run-time)? [**]

          23. How do I set the Windows wallpaper at runtime? [**]


   E. CALLING THE WINDOWS API AND DLLs IN GENERAL

          1. What is the Windows API?

          2. How do I call a DLL?

          3. What about DLL calls that require callbacks?

          4. Tips for calling DLLs (such as the Windows API)


   F. VISUAL BASIC AND DATABASES

          1. Why can't I use an index with my VB accessed database? [++]

          2. "Can't find installable ISAM" or Why does my compiled VB
              database app generate an error when it ran just fine in the
              design environment? [++]

          3. Is the Access Engine and Visual Basic Pro good enough for
             database work? [++]

          4. How do you avoid the "Invalid use of null" error when reading
             null values from a database?

          5. What is "NULL"?

          6. How can I access a record by record number? [++]

          7. How about Access 2.0 compatibility? [++]

          8. Tips for VB database programming: [++]

          9. How come I get a "No Current Record" error when I use a a Data
              Control on an empty table?

          10. How can I speed up my VB database application? [++]

          11. How do I get a bitmap picture in a field in an Access
              database?

          12. What is "Reserved Error -1209"?

          13. "Cannot perform operation. illegal.." with Paradox 3.5
              table(s)

          14. I'm getting error message "Reserved Error [-nnnn] ("There is
              no message for this error")" from Jet Engine 2.0. Huh? [**]

          15. Why do I get "object not an array" when I try reference the
              fields of a global object variable which I have set to a
              table? [**]


   G. DISTRIBUTING VISUAL BASIC APPLICATIONS

          1. What are some tips for using Setup Wizard?

          2. Are there restrictions on what I can distribute with my VB
             program?

          3. What alternatives to setup wizard do I have?

          4. Do I need to worry about users who have Progman replacements
             such as Norton Desktop and PC Tools?

          5. Can I distribute my app without vbrunXXX.dll?

          6. Why won't my setup program install commdlg.dll et. al.?

          7. Where do I install VBXs and DLLs?


   H. MISCELLANEOUS TIPS AND INFORMATION

          1. Multiple identifiers after the DIM statement can be confusing

          2. "Clean up" your project before final EXE compilation.

          3. Multiple END statements can be dangerous; or, The program that
             refused to terminate.

          4. What are the latest versions of the various files used by VB?


   I. VISUAL BASIC FOR APPLICATIONS (VBA)

          1. Any tips for VB/Win 3 programmers moving to VBA?

          2. Does VBA support VBXs?

          3. How do I access properties on my dialog boxes in VBA?

          4. How do I use database routines from Excel VBA?

A. PREFACE [++]


1. About this document

   This document is a compilation of frequently asked questions and their
   answers about Visual Basic for Windows and Visual Basic for Applications
   which have been gathered from posts to the comp.lang.basic.visual.*
   newsgroups.  Although efforts have been made to find obvious errors,
   there is no guarantee that the information in this document is error-
   free. Neither the FAQ maintainer nor anyone else associated with this
   document assume ANY liability for the content or use of this document.
   If you find any errors, please report them to the address given below.

   This FAQ document is protected by international copyright regulations.
   Permission is granted to distribute it freely, both in electronic and
   written format, provided no charge is made. Also, do not make changes to
   this document without the consent of the maintainer. Usenet netiquette
   applies.

2. Where to get the VB/Win FAQ

   Most FAQs (including this one) are available at the anonymous ftp
   archive site "rtfm.mit.edu". All parts of the VB FAQ may be found here:

     ftp://rtfm.mit.edu/pub/usenet/comp.lang.basic.visual.misc/

   **Alternative Sites**:
   The following are alternative sites to rtfm:

   N. America: ftp.uu.net             /usenet/news.answers
   Europe:     ftp.uni-paderborn.de   /pub/FAQ
               ftp.Germany.EU.net     /pub/newsarchive/news.answers
               grasp1.univ-lyon1.fr   /pub/faq
               ftp.win.tue.nl         /pub/usenet/news.answers
               ftp.sunet.se           /pub/usenet
   Asia:       nctuccca.edu.tw        /USENET/FAQ
               hwarang.postech.ac.kr  /pub/usenet/news.answers

   (FYI:  "rtfm" stands for "Read The ******* Manual".  I kid you not!)
   [Andre van Meulebrouck (vanmeule@ils.nwu.edu)]

   You can also have the VB FAQs e-mailed to you by sending a message to
   "mail-server@rtfm.mit.edu" with ONLY the text

     send usenet/comp.lang.basic.visual.misc/*

   in the BODY of the message.

   Alternative mailservers for those who have no ftp access
     ftpmail@decwrl.dec.com or ftpmail@cs.uow.edu.au
     bitftp@pucc.princeton.edu or ftpmail@lth.se
     bitftp@dearn or to bitftp@vm.gmd.de (Europe only)
     ftpmail@ftp.uni-stuttgart.de
     ftpmail@grasp.insa-lyon.fr or ftpmail@ieunet.ie
     bitftp@plearn.edu.pl or bitftp@plearn (Europe)
     ftpmail@doc.ic.ac.uk or ftpmail@sunsite.unc.edu
   [thanks to Jakob Faarvang (jakobf@colossus.ping.dk)]

   For all mailservers:
   Use the "index" command to get a list of files available at the site.
   Use the "help" command to get more detailed instructions.
   (NOTE: commands are in BODY of mail message!)

3. Kudos & comments

   In this document, whenever a long line of code must be split into two or
   more lines of text in the code examples, a | symbol will precede each
   line which should be appended to the line above it.

   As the FAQ maintainer, I don't have time to explore all of the aspects
   of Visual Basic. Neither have I time or knowhow to personally answer
   direct technical questions thoroughly. I rely on your submissions to
   improve the quality and inclusiveness of this document. If you have
   found a VB hint, tip, trick, work-around, etc., please write it up and
   send it to me!

   Jan Steinar Haugland (Jan.Haugland@uib.no), VB/Win FAQ maintainer

   Please note that my first language is not English. You can safely ignore
   all typos, but if you find an error that is so embarrassing you can't
   help pulling your hair and screaming loud, just send me a note and I'll
   correct it quietly. OK?

   This document is a collective effort! I would like to thank all
   contributers, and also all those who have given constructive feedback.
   This FAQ is now widely distributed in the net community.

   Special thanks to the following people who have made many and invaluable
   contributions to the VB/Win FAQ:  Kris Nosack (the previous maintainer),
   Peter Millard, Nic Gibson, Mr. "D" (the anonymous contributor), George
   Tatge (gat@csn.org), Andy Dingley (dingbat@codesmth.demon.co.uk), Ayn
   Shipley (ashipley@hookup.net) and those I may have forgotten (sorry).

   John McGuire (jmcguire@jax.jaxnet.com), a longtime VB user, recently
   went through the FAQ and found lots of things worth his comments. Many
   of his corrections and suggestions are implemented throughout. Thanks!

   Everybody: Your help is GREATLY appreciated!


B. GENERAL VISUAL BASIC QUESTIONS


1. Does VB/Win make standalone .EXE files?

   VB/Win produces .exe files, but they are not standalone. All VB/Win
   programs must be distributed with the VBRUNx00.DLL file (where x is the
   major version number). This DLL must accompany all VB/Win programs, but
   only one such file should reside on every system where VB programs are
   used.

2. What is the current version of Visual Basic for Windows?

   VB/Win is currently at version 3.0

3. Where can I get updated VB and other Microsoft files?

   Microsoft Software Library (MSL) is accessible from the following
   services:

   - Compu$erve

     GO MSL
     Search for <filename.EXE>

   - Microsoft Download Service (MSDL)
     Dial (206) 936-6735 to connect to MSDL

   - Internet (anonymous FTP)
     ftp ftp.microsoft.com
     Change to the \softlib\mslfiles directory

     (There are a LOT of files in this directory! It is not
     advisable to list all the files unless you have good time.
     See map below.)

4. Help! I am lost on ftp.microsoft.com.

   You no longer have to be! The site have been reorganised, and you'll
   find the file DIRMAP.TXT in root (or whatever it's called on a 3.5 NT
   server). Here's the file as I found it (stolen ruthlessly from the
   server for yoru convenience):

   *-------------------------------------------------------------------*
   This file is to help you find your way around ftp.microsoft.com. This
   file only covers the directory structure two levels deep. If you see a
   'kb' directory in a second level directory, it contains all of the
   information regarding that second level directory.  For example, the
   /developr/win32dk directory has a kb directory in it.  This kb directory
   contains all of the articles for any 32 bit development kit.

   ROOT DIRECTORY         SUB DIRECTORY         CONTENTS
   -----------------------------------------------------------------------
   ADVSYS                          Advanced Systems, Networks, Mail
                       LANMAN      LanMan & other networks
                       MAIL        Mail and Schedule+
                       MSCLIENT    Microsoft Networking Client
                       SQL_ODBC    SQL and ODBC
                       WINNT       Windows NT
                       WINSOCK     Windows Sockets information

   DESKAPPS                        Desktop Applications
                       ACCESS      Access
                       DOSWORD     Word for MS-DOS
                       EXCEL       Excel
                       GAMES       Entertainment Packs, Flight Sim, etc.
                       HOMEAPPS    Home applications
                                   (Fine Artist, Creative Writer)
                       MISCAPPS    Other applications
                       MMAPPS      Multimedia Titles
                       OFFICE      Microsoft Office
                       POWERPT     PowerPoint
                       PROJECT     Project
                       PUBLISHER   Publisher
                       WORD        Word for Windows & Macintosh
                       WRKS_MNY    Works and Money

   DEVELOPR                        Developer Tools and Information
                       BASIC       Quick Basic & other Basics
                       DEVCAST     DevCast information
                       DEVUTIL     MS Test, Delta, EXEMOD, EXEPACK,
                                   & LIB Utility
                       DRG         Developer Relations Group
                       FORTRAN     Fortran and Fortran PowerStation
                       FOX         FoxPro and FoxBase
                       MAPI        Messaging API information
                       MASM        Macro Assembler
                       MSDN        Microsoft Developer Network
                       MSJ         Microsoft Systems Journal
                       OLE         OLE
                       TAPI        Telephony API information
                       VB          Visual Basic
                       VISUAL_C    Visual C++, MFC, & other C products
                       WIN_DK      Windows SDK, DKs & At Work
                       WIN32DK     32 bit Development Kits

   MSEDCERT                        Microsoft Education and Certification
                       EDUCATIO    Microsoft Education information
                       CERTIFIC    Microsoft Certified Professional info

   MSFT                            Microsoft shareholder information

                       ANNREPT     Microsoft Annual Report
                       BACKGRND    Background information on Microsoft
                       PRESSREL    Microsoft Press Releases
                       SEC         Recent filings with the Securities and
                                   Exchange Commission

   SOFTLIB                         Instructions & index for software
                                   library

                       MSLFILES    Software library files (> 1500 files)

   PEROPSYS                        Personal Operating Systems and Hardware

                       HARDWARE    Mouse & other Hardware
                       MSDOS       MS-DOS
                       WINDOWS     Windows (all versions)
                       WIN_NEWS    Information on Windows "Chicago"

   TECHNET                         Information on TechNet
                       SERVDIR     Microsoft Services Directory

   *-------------------------------------------------------------------*

   NOTE: Directory and file names at ftp.microsoft.com are NOT case
   sensitive.

   Thanks to Richard Mason (richard@whitney.demon.co.uk) for the map he
   made for us before this long overdue reorganisation, and thanks for
   bringing this to my attention.

5. Where can I get good up-to-date information about VB?  [++]

   If you do any VB programming at all, you really should get the latest
   copy of the Microsoft Knowledge Base from one of the sources listed
   above!  The filename is VBKB.EXE or VBKB_FT.EXE for the version with
   full text searching. The Knowledge Base is a Windows help formatted
   document that is updated almost monthly. (Beware: The files are huge!)

   The EXE files on ftp.microsoft.com (and other places) are simple self-
   extracting files. They don't do any automatic updating of your system,
   just dump the file(s) inside them in the current directory on your disk,
   uncompressed and ready for use. Just replace the old files on your
   system with the new files (same name, usually).

   This FAQ (ahem) is a pretty good source as a digest of many of the VB
   issues that are discussed in the comp.lang.basic.visual.* newsgroups,
   but as such the information contained in this FAQ may not have been
   thoroughly tested or verified.

   For easier access to and use of this FAQ document, get the Windows Help
   file format FAQ doc by anonymous ftp to quasar.sba.dal.ca and look under
   /www/hlp. The .HLP version is made by Tim Roberts
   (TJR@SBACOOP.SBA.DAL.CA). This is HIGHLY RECOMMENDED.

   WWW pages for VB? Carl 'n Gary's Visual Basic HomePage is a good place
   to start:

      http://www.apexsc.com/vb/

   This page has hotlinks to lots of goodies, including the FAQs, clbv.*
   archives (with search tool), etc. [Gary Wisniewski (gary@apexsc.com)]

   Dave McCarter puts out a nice Windows help formatted document called
   "Visual Basic Tips and Tricks". A good resource with information that
   isn't found in the Knowledge Base. It can be found by anonymous ftp to
   ftp.cica.indiana.edu /pub/pc/win3/programr/vbasic/ as VBTIPS??.ZIP,
   where '??' is the version number (yes, get the one with the highest
   number).

   Mark Schoonover has started a monthly magazine called _VBWin
   Programmer's Magazine_ that is compiled around the Discussion of
   Microsoft Visual Basic and Related Issues mailing list. This magazine is
   available at the usual ftp sites like cica and at his BBS (619) 571-
   2846. Mark can be contacted at schoon@cts.com. It also has its own
   anonymous ftp site: ftp.cts.com in the /pub/schoon/VBWM.Issues
   directory.

   There is presently an effort to put together a VB code library so that
   VB users can share their best - and trickiest - programming work. The
   code library project is being spear headed by Hein Ragas who has managed
   to get a directory on CICA for code snippets to be deposited. Stayed
   tuned to comp.lang.basic.visual.misc for more information.

   There's a VISBAS-L mailing list for Visual Basic (Thanks to David Liden
   (DL9U@Virginia.EDU) for tracking it down for me when it moved). You can
   subscribe to this mailing list by sending an email to

     listserv@listserv.tamu.edu

   Place the following text in the *body* of the message (no, not the
   subject line):

     SUB VISBAS-L Real Name

   Where Real Name is just that, *your full real name* not your email
   address. Note that the traffic on this list may overflow your mailbox if
   you have a limited mail buffer. Expect around 40-50 messages every
   weekday, a bit less during weekends. Also, to unsubscribe, do as above
   but with "UNSUB" in the body of the message to the LISTSERV address,
   *not* to the VISBAS-L list address itself (Believe it or not, we usually
   receive 2-3 sub/unsub mails every day on the list, and we're really fed
   up!) Also, this mail server was split and a new list called VBDATA-L was
   made for Vb database (Jet) related topics. Same procedure for
   registering (SUB VBDATA-L Real Name).

   The address for the MS ACCESS listserver is listserv@indycms.bitnet or
   listserv@indycms.iupui.edu The list name is ACCESS-L. To subscribe, you
   follow the same procedure as for the other lists.

   Sorry, I know no mailservers or other Internet resources dedicated to
   VBA specifically. Send me any information you may have, and I'll bring
   it on.

   There are several Usenet newsgroups dedicated to MS Windows programming
   and use. Those groups that may be of special interest to VB programmers
   are marked with *:

   comp.os.ms-windows.misc
   comp.os.ms-windows.programmer.misc
   comp.binaries.ms-windows
   comp.os.ms-windows.advocacy
   comp.os.ms-windows.announce
   comp.os.ms-windows.apps
   comp.os.ms-windows.nt.misc
   comp.os.ms-windows.nt.setup
   comp.os.ms-windows.programmer.tools     *
   comp.os.ms-windows.programmer.win32
   comp.os.ms-windows.setup                *
   comp.os.ms-windows.programmer.winhelp   *
   comp.os.ms-windows.programmer.networks
   comp.os.ms-windows.programmer.graphics
   comp.os.ms-windows.programmer.controls  *

   The latest groups have been added to split the enormous traffic on the
   *.misc groups down in managable chunks. However, the second group
   (.programmer.misc) contains lots of interesting info (mostly C related),
   if you have the time to read it all!

   Also note comp.lang.pascal which is a very good newsgroup for Pascal,
   including Borland Pascal, Turbo Pascal for Windows and Delphi.

   Please don't use this guide to find out where you should crosspost VB
   questions. Check the charter for each group before posting to it. If you
   are sure that your crosspost is legitimate, please note the crossposting
   in the text.

   NOTE: PLEASE don't post VB stuff to comp.lang.visual. This group has
   *nothing* to do with Visual Basic, and the academics discussing "real"
   visual programming there are very, very annoyed at what they call
   "quasi-visual" stuff and postings about those languages to their group.

   If you have a Compu$erve account, you will find a forum for Visual Basic
   there, including some support from Microsoft:

   MS BASIC Forum    (GO MSBASIC)

   Message Sections Available:             Libraries Available:
    1 Forum News/Info                       1 MS Info and Index
    2 Setup Wizard/Kit                      2 Setup Wizard/Kit
    3 Data Access Objects                   3 Data Access Objects
    4 The Data Control                      4 The Data Control
    5 Programming Issues                    5 Programming Issues
    6 ODBC Connectivity                     6 ODBC Connectivity
    7 SQL Queries                           7 SQL Queries
    8 ProEdition Controls                   8 ProEdition Controls
    9 Calling API's/DLL's                   9 Calling API's/DLL's
   10 Using OLE/DDE                        10 VBWIN-ODBC/Database
   11 MSCOMM control                       11 MSCOMM control
   12 MCI/MAPI controls                    12 MCI/MAPI controls
   13 DOS Visual Basic                     13 DOS Visual Basic
   14 DOS and Mac Basic                    14 DOS and Mac Basic
   15 Suggestions/Mktg.                    15 Suggestions/Mktg.
   16 CDK                                  16 CDK
   17 3rd Party Products                   17 3rd Party Products

   There are magazines dedicated to VB. The best known is Fawcett Technical
   Publications' _Visual Basic Programmer's Journal_ (VSPJ). Phone 800-848-
   5523 (for US credit card orders) or 303-541-0610 (int'l and US other
   orders), Email 74003.224@compuserve.com to Shirley Modric for
   subscription info. Address is 280 Second Street, Suite 200, Los Altos,
   CA 94022-3603 USA.

   From Randy Coates (rcoates@telerama.lm.com):
   I currently subscribe to "Inside Visual BASIC for Windows" from the Cobb
   Group.  Although it is a helpful monthly paper (about 14 pages per
   publication), I find it to be overpriced when compared to VB Programmers
   Journal.  Here is the information anyway: Domestic $59/yr ($7.00 each);
   Outside US $79/yr ($8.50 each)
   Phone: Toll Free: 800-223-8720),  Local: 502-491-1900, Customer
   Relations Fax: 502-491-8050, Editorial Department Fax: 502-491-4200.
   Address: _Inside Visual BASIC for Windows_, 9420 Bunsen Parkway, Suite
   300, Louisville, KY  40220.

   (Note: for completeness other VB magazines should be listed, and I would
   like to receive info on those!)

6. Are there any examples of commercial applications built using Visual
   Basic? [++]

   Profit by Microsoft was written mostly in Visual Basic. In fact, Profit
   was one of three programs selected as PC Magazine's Editor's Choice
   among Windows small business accounting packages. Most of the current
   version of Quicken was written in VB2. The viewer/launcher/installer in
   the oh-so-popular Way Cool [Topic] for Windows series of CD-ROMs was
   written in VB3.

   Microsoft uses VB extensively for smaller utilities. 3 of the small apps
   in the Windows and Windows for Workgroups Resource Toolkits are written
   in VB. Also, if you have the Microsoft Bookshelf CD-ROM, you will notice
   that the MVOPTION.EXE program, which is an "options" program for MS
   Viewer, is created in VB.

   Note: The existence of VBX files in a package doesn't ecessarily mean
   that it was written in VB. The most popular C++ compilers also support
   VBXes.

7. Limits of VB? [**]

   Are you kidding? VB have *no* limitations... Uh, yeah ;-)

   For starters:

   a. It's not a true compiler, hence it's slow for non-interface stuff
      (it's of course slow for interface stuff as well, but that's
      *Windows* not VB)

   b. It's not really object-oriented (Try looking for the parent of ie. a
      line control, and you'll wonder why it has no hWnd  - SpyWorks is an
      add-on you may need if this is annoying)

   c. A statement must be on a single line! Expect a fix in VB4.

   d. No arrays of constants.

   e. Your Complaint Here!

   An enormous amount of contributers to this topic! Can you guess why?
   [Entry suggested by Andre van Meulebrouck (vanmeule@netcom.com)]


C. COMMON VISUAL BASIC PROGRAMMING QUESTIONS

1. What's the difference between MODAL and MODELESS forms?

   MODAL forms are forms which require user input before any other actions
   can be taken place. In other words, a modal form has exclusive focus
   until it is dismissed. When showing a modal form, the program pauses at
   the SHOW command until the modal form is either hidden or unloaded. The
   internal MsgBox and InputBox forms are examples of modal forms. To show
   a form modally, use the syntax:

     MyForm.SHOW 1

   MODELESS forms are those which are shown but do not require immediate
   user input. MDI child forms are always modeless. To show a form
   modeless, use the syntax:

     MyForm.SHOW

2. When/Why should I use Option Explicit?

   Option Explicit forces you to declare all variables before using them.
   Opinions vary greatly on this subject. The main reason to use the OPTION
   EXPLICIT statement at the top of all modules is to minimize the amount
   of bugs introduced into your code by misspelling a variable name. Most
   variants of BASIC (including VB) have the capability to create variables
   'on the fly' (without any declarations). This capability can be a double
   edged sword.

   At the minimum, some suggest using the DEFINT A-Z statement in leu of
   OPTION EXPLICIT. This statement will cause any variables which are
   created on the fly to be created as integers as opposed to variant (VB
   3.0) or single precision (VB 1.0 and 2.0). (Integers take up less
   memory).


   The OPTION EXPLICIT statement causes VB to 'disable' its ability to
   create variables on the fly. Thus, all variables must be declared using
   a DIM or REDIM statement. All variables not declared will cause an error
   when the OPTION EXPLICIT statement is used. This will eliminate bugs
   caused by a misspelled variable. The option works module-wide, so you
   can have some modules with and some without this option in your project.

3. Why does everybody say I should save in TEXT not BINARY?

   Actually, saving in binary mode is a bit faster, so why do we recommend
   you to save in text?

   If you save the source and the project as text, it becomes ASCII (or
   really, ANSI) code that you can edit with any text editor or (if you are
   careful when you save) word processor. If you save in binary, only the
   VB development environment, current or later versions, will understand
   the code. The Setup Wizard can not scan binary projects. Also, source
   documenters and other programming tools usually require text mode. If
   you use text, you can use a simple text editor (ie. notepad) to cut and
   paste code from other source/form modules into your current project.
   Some 'tricks' (like making an array of 1 control into a single non-array
   control again) is easily done with an editor but not that easy in the
   environment. If you want to print your project to paper the file|print
   option in the VB environment is often not good enough; you may want to
   import the text files into your word processor. And, finally, if
   something goes wrong (only one byte is changed!) you may be out of luck
   in binary mode. In text mode you will more easily be able to fix it.

4. Is the Variant type slower than using other variable types?

   Generally, yes, if we are talking numeric variable types. The Variant
   type also increases memory overhead. To test the speed difference, try
   the following piece of code in something like a button_click event and
   keep the debug window on the screen:

     Dim Va As Variant
     Dim In As Integer
     T1! = Timer
     For i% = 1 To 32766
       Va = i%
     Next i%
     T2! = Timer
     Debug.Print "With variant:  "; Format$((T2! - T1!), "0.0000")
     T1! = Timer
     For i% = 1 To 32766
       In = i%
     Next i%
     T2! = Timer
     Debug.Print "With integer:  "; Format$((T2! - T1!),"0.0000")

   This test shows (on our test system) that integers are ~60% faster!
   However, for strings there where no real difference, or in some
   instances, variants were faster than strings for routines with heavy
   conversion usage. For the best result in your application, test your
   routines directly.

5. How do I make a text box not beep but do something else when I hit the
   Enter key?

   Put "something else" in your _KeyPress event, depending on what you
   really want. This code example makes *nothing* happen, for an extended
   period of time:

     Sub Text1_KeyPress (KeyAscii As Integer)
         If KeyAscii = 13 Then   '13 is Key_Return
            KeyAscii = 0
         End If
     End Sub


   This might not be a very nice thing to do, since your users usually have
   some intention when they press Enter. Often they will want to jump to
   the next control, like the Tab key does. To have the Enter key emulate
   the Tab key action, you will need to add the line 'SendKeys "{tab}"'
   above 'KeyAscii=0' in the example above (Yes, I thought KeyAscii=9 works
   but it doesn't! Tab is obviously handled by Windows on a lower level).

   By the way, you'll also find this in the Microsoft VB Knowledge Base
   (see KB Q78305 and Q85562).

   Note: If MultiLine=True you will *not* want to disable the normal
   behaviour of the Enter key.

6. How do I implement an incremental search in list/dir/combo/file boxes?

   This is your lucky day. Dan Champagne (Dan_Champagne@dell.com) made some
   VB code (no DLLs are necessary!) which easily provides this feature for
   your applications:

     ' Code by Dan Champagne
     ' 4/18/94

     ' This code can be used to do an incremental search in either a
     ' list box, dir, combo, or a file box. The following code is set
     ' for a file box called FILE1. To make it work with a list box, or
     ' a file box with a different name, change all occurences of FILE1
     ' with whatever you or VB has named your list, combo, dir, or file box.
     ' There are two places where you will need to change these. They are
     ' on the last couple of lines in the KeyPress code.
     ' Also, thanks to John Tarr for helping debug the code.

     'In a .BAS file, add the following:
     'searchme$ is a global vaiable that will keep track of what the
     'user has typed so far.
     Global searchme$

     'The following needs to be on one line.
     Declare Function SendMessageBystring& Lib "User" ALIAS
     |"SendMessage" (ByVal hWnd%, ByVal wMsg%, ByVal
     |wParam%, ByVal lParam$)

     Global Const WM_USER = &H400
     Global Const LB_SELECTSTRING = (WM_USER + 13)
     Global Const LB_FINDSTRING = (WM_USER + 16)

     'In File1 under keydown, add the following:
     'This checks if the user has pressed the up or down arrow.
     'If they have, reset searchme$ to "".
     If KeyCode = 40 Or KeyCode = 38 Then
        searchme$ = ""
     End If

     'In File1 under lostfocus, pathchange, patternchange, and click add:

     'If the user has done any of the above, reset the searchme$
     'string.
     searchme$ = ""

     'In File1 under keypress add:

     Dim result&

     Select Case KeyAscii
         Case 8     'Backspace
             If searchme$ <> "" Then
                 searchme$ = Left$(searchme$, Len(searchme$) - 1)
             Else
                File1.ListIndex = 0

             End If
             KeyAscii = 0
             Exit Sub
         Case 27    'Escape
             searchme$ = ""
             KeyAscii = 0
             Exit Sub
         Case 13    'Enter
             searchme$ = ""
             KeyAscii = 0
             Exit Sub
         Case Asc("a") To Asc("z"), Asc("A") To Asc("Z"), Asc("'"),
         |Asc("."), Asc(" "), Asc("0") To Asc("9")
             searchme$ = searchme$ & Chr$(KeyAscii)
             KeyAscii = 0
     End Select

     result& = SendMessageBystring(FILE1.hWnd, LB_FINDSTRING,
     |0, searchme$)

     If result& = -1 Then
        searchme$ = Left$(searchme$, Len(searchme$) - 1)
     Else
        result& = SendMessageBystring(FILE1.hWnd, LB_SELECTSTRING,
        |-1, searchme$)
     End If

7. How do I get the Tab key to be treated like a normal character?

   You must set TabStop = False for ALL controls on the active form. Then
   you will be able to insert "tab" (chr 9) characters in controls like the
   text box.

   If you feel you need the Tab key to behave "normal" (ie. jump to next
   control) outside this specific control, it is trivial to emulate its
   functionality in code:

     Sub Command1_KeyDown (KeyCode As Integer, Shift As Integer)
       If KeyCode = 9 Then
         If Shift = 0 Then
            Command2.SetFocus 'Tab=Next control
         ElseIf Shift = 1 Then
            Command3.SetFocus 'Shift-Tab=Prev.ctrl.
         End If
       End If
     End Sub

   ...etc.

8. How do I make an animated icon for my program?

   For an example on how you change the icon for your application as it is
   displayed when it is minimized, see the example REDTOP in the
   \samples\picclip directory for VB/Win 3 Pro. This demonstrates a fancy
   animated icon.

9. What is passing by reference?

   Arguments are either passed by reference or by value. When they are
   passed by value, they cannot be changed by the procedure or function
   they are passed to. They *can* be altered when passed by reference,
   since passing by reference is just passing the address.

   Note that procedures are less strict about variable types when you use
   BYVAL. If you declare that your Sub takes a Variant, VB takes that
   seriously and gives a nasty "mismatch error" if you try to pass ie. a
   string to it. Make it ByVal (at the cost of some speed) and your sub
   will be more tolerant.

   Also note the following nasty trap:  Arguments are passed by reference
   unless enclosed by parentheses or declared using the ByVal keyword.
   [VBWin Language Ref., p. 55]

10.I get a "file not found" error on the IIF function when I distribute by
   program. Uh?

   There's a documentation error, since the manual does not tell you that
   the IIF function requires the file MSAFINX.DLL to be distributed with
   your application. No, IIF is not financial (I should know, I study
   finance right now, or at least I should be doing that ;-] ).

11.Is there any way to pass a variable to a form apart from using global
   variables? [++]

   The standard workaround is to put an invisible text box (or caption or
   any other control that suits your use.) on the target form and access it
   by Form.textbox = "value". Then you can use the Change event of that
   control to do anything you want in that form. Also, check out the .Tag
   property which is a "what-you-want" property where you can hook any
   string you want onto a control. This property can also be accessed from
   other modules.
   [Dave Mitton (mitton@dave.enet.dec.com)]

   Perhaps a more elegant and flexible way is to implement a stack with
   global routines. I've done this for a math project, but this stack was
   rather complicated and special purpose (and inspired by HP calculators,
   of which I'm a great fan).

   Jan G.P. Sijm (jan.sijm@intouch.nl) has implemented some routines for
   general stacks:

   '--------------------------------------------------------------------
   Option Explicit                        'Variable declarations required
   Dim m_vStack() As Variant              'Stack of variant types

   '*-------------
   '*  This function will pop a value of a stack of variant
   '*  values. The value to be popped (e.g. the variable it
   '*  is assigned to) must have one of the basic variable
   '*  types that Visual Basic supports. The type of the
   '*  return value is determined by the type of the variable
   '*  it is assigned to.
   '*
   '*  Input    : None
   '*  Modifies : m_vStack, Stack of variant's
   '*  Return   : Value of last pushed variant
   '*-------------
   Function stkPop () As Variant
     Dim iM As Integer
     iM = UBound(m_vStack)                'Get current stack size
     stkPop = m_vStack(iM)                'Pop value from stack
     iM = iM - 1                          'Decrement number of elements
     ReDim Preserve m_vStack(iM) As Variant
   End Function

   '*-------------
   '*  This function will push a value onto a stack of
   '*  variant values. The value to be pushed must have one
   '*  of the basic variable types that Visual Basic supports
   '*
   '*  Input    : vValue, Value to be pushed
   '*  Modifies : m_vStack, Stack of variant's
   '*-------------
   Sub stkPush (ByVal vValue As Variant)
     Dim iM As Integer
     On Error Resume Next                 'Trap for undimensioned array
     iM = UBound(m_vStack)                'Get current array size
     iM = iM + 1                          'Increment number of elements

     ReDim Preserve m_vStack(iM) As Variant
     m_vStack(iM) = vValue                'Push value on stack
   End Sub

   'This is a short example of how the stack routines can be used in a
   'Visual Basic program. This example will push three parameters onto
   'the stack. A modal dialog is displayed. The dialog will pop the
   'parameters from the stack and set edit controls with the values.

   Sub ShowDialog()
     '
     '  Push the parameters for the dialog
     '  onto the stack and display the dialog
     '
     stkPush sName
     stkPush sStreet
     stkPush sCity
     dlgPerson.Show MODAL
   End Sub

   Form_Load()
     '
     ' Pop the parameters of this dialog from the
     ' stack in REVERSED ORDER and place the values
     ' in the appropriate edit controls.
     '
     dfCity.Text = stkPop()
     dfStreet.Text = stkPop()
     dfName.Text = stkPop()
   End Sub
   '--------------------------------------------------------------------

12.How should dates be implemented so they work with other language and
   country formats?

   If you use ie. MM/DD/YY format dates in a program, you will get either a
   runtime-error (ie. month>12) or the wrong date (ie. March 12 instead of
   December 3) when your program is used in Europe. And vice versa, of
   course. Even Microsoft's own example programs (like the MAPI sample)
   make this stupid mistake and fail miserably. Use the Format command to
   make sure you get the date you want. For example:

     strTodaysDate = Format[$](Now, "Short Date")

   As a side note, Microsoft has taken much heat on the newsgroup for VB's
   bad support for internationalization! Just try to make a date literal in
   source code that works everywhere as a little exercise. Answer elsewhere
   in this document. No prizes  :-)

13.Can a VB application be an OLE server?

   No. You'll have to use an external DLL/VBX. If you see any examples,
   please tell the newsgroup.

14.How do I dial a phone number without using the MSCOMM VBX?

   The MSCOMM VBX that comes with VB/Pro is great for creating
   communication programs, but it's overkill for dialing a phone number.
   Try the following code:

     PhoneNumber$ = "(123)456-7890"
     Open "COM2" For Output As #1   'or COM1
     Print #1, "ATDT" & PhoneNumber$ & Chr$(13)
     Close #1

   Ian Storrs <exuian@exu.ericsson.se> informed me that he had experienced
   problems with this when the VB program was run from a network drive. A
   file named "COM1" was created on the disk! This trick is probably not a

   good idea for bigger applications, but it's nice for small personal
   utilities.

15.I have [several] megabytes of memory. Why do I get an "out of memory"
   error?

   Unfortunately, Microsoft has been more famous for memory barriers than
   anything else. This is a late descendant of the infamous 640K barrier
   that has been plaguing us for years. Although Windows allows the user to
   access several megabytes of memory, it uses two limited (64K) memory
   areas called User Heap and GDI Heap for some specific data structures.
   Go to the Help|About box in Program Manager to see the percentage of
   free resources in the *most* exhausted heap. If these areas are
   exhausted, you are out of luck. VB programs are unfortunately rather
   greedy on these structures. Windows 4 is supposed to free us from this
   limitation...

   Note that every visible control (ie every button) is a window to
   Windows. Every new control takes up some bytes in the precious User
   heap.

   Also, there is another way to run out of memory in Windows, not related
   to VB. Windows requires free Upper Memory Area (UMA, also called Upper
   Memory Blocks, not to be confused with High RAM, which is the first 64K
   of extended memory) to do certain tasks. If you use QEMM or DOS 6+
   MemMaker and you have many device drivers (network, etc) this area may
   have been filled up before you launch Windows. You will then be unable
   to start applications, even though you have plenty of free RAM. The
   problem can be solved with careful memory setup, but this is far beyond
   the scope of this FAQ.

   On a completely unrelated problem: When you run a program with an
   outline control with some ATI graphics cards, it may crash with just
   that error message. (see Knowledge Base Q100194 PRB: "Some ATI Video
   Drivers Hang When Using MSOUTLIN.VBX")

16.How do I mimic a toggle button? [++]

   The only "fix" we know for this problem is to use a picture control to
   mimic the action of a button or button3d control. You need two bitmaps,
   one for buttonup and one for buttondown (and perhaps one more for
   inactive state). This is a kluge, we know. Look at the button bar used
   in the MDINOTE sample program supplied with VB for an example of this.
   (Note: You can't use an image control since it doesn't take click
   events)

17.How do I get my application on top?

   To force a form to the front of the screen, do the following command:

     Form1.ZOrder

   To make the application *stay* on top, put the Zorder command in a Timer
   event repeatedly called, say, every 1000 msecs. This makes a "softer"
   on-top than other methods, and allows the user to make a short peek
   below the form.

   There are two different "Zorder"'s of forms in Windows, both implemented
   internally as linked lists. One is for "normal" windows, the other for
   real "topmost" windows (like the Clock application which is distributed
   with MS Windows). The Zorder command above simply moves your window to
   the top of the "normal" window stack. To make your window truly topmost,
   use the SetWindowPos API call like this:

     'Make these declares:
     Declare Function SetWindowPos Lib "user" (ByVal h%,
     |ByVal hb%, ByVal x%, ByVal y%, ByVal cx%, ByVal cy%,
     |ByVal f%) As Integer
     Global Const SWP_NOMOVE = 2

     Global Const SWP_NOSIZE = 1
     Global Const FLAGS = SWP_NOMOVE Or SWP_NOSIZE
     Global Const HWND_TOPMOST = -1
     Global Const HWND_NOTOPMOST = -2

     'To set Form1 as a TopMost form, do the following:
     res% = SetWindowPos (Form1.hWnd, HWND_TOPMOST, 0, 0,
     |0, 0, FLAGS)
     'if res%=0, there is an error

     'To turn off topmost (make the form act normal again):
     res% = SetWindowPos (Form1.hWnd, HWND_NOTOPMOST, 0, 0,
     |0, 0, FLAGS)

18.Is there a way to break long lines in VB code?

   There is unfortunately no line continuation character in VB/Win 3.0.
   Excel 5 VBA does, however, use Space+Underscore (" _") as a line
   continuation character, and we hope this will be included in the next
   version of VB.

   There are a few tricks you can use to reduce line length, but
   unfortunately there is very little to do with DECLARE statements which
   can get very long.

   Print your source in landscape   :-/

19.How do I remove/change the picture property of a control at design time?

   Mark the (bitmap) or (icon) text in the property window and press Del or
   Backspace. "No!" I hear you cry, "It doesn't work". Well, it does if you
   first select the object from the combo box at the top of the Properties
   Window, and then immediately afterwards  doubleclick (or paint over) the
   "(bitmap)" text and press Del. Alternatively, just click on another
   control, then click back to the first control. Now Del works. Who said
   "bug"?

   If you want to paste your picture directly into the VB program by
   pressing Ctrl-V when you are editing the picture property, you will have
   to use a semilar procedure: select the control, select the property,
   press Ctrl-V. If you try it again without deselecting the control first
   (or selecting it from the combo box), it doesn't work.

20.Is a [foo] VBX/DLL available as shareware/freeware?

   Part 4 of the FAQ is Adam Harris' excellent "Shareware Custom Controls
   List". Please consult this list before you post this question.

   The following type of controls are NOT known to be available as sw/pd/fw
   for Visual Basic, only as commercial toolboxes (If you feel like making
   any of these for VB and sharing it for a modest fee, you will become
   very popular!):

   a. ZModem communication control/source

   b. Rich Text Format-control or other mixed font/word processor control
      (rumours indicate that this will be in the Windows 4 API, and
      therefor available from VB)

   c. Matrix math

   If any of these should be available, please tell us.

21.How do I make my applications screen-resolution independent?

   There are two methods: Either get a custom control that does the job for
   you, or you write lots of complicated code in the Load and Resize
   events.

   For the first option, check out VideoSoft's $hareware VSVBX.VBX
   (download VSVBX.ZIP from Cica or mirrors). It has a will of its own, as
   you will experience, but it's generally better than trying what is
   described below.

   For the brave (or stupid), try to write "screen resolution-smart code"
   in the form's Load event. If the form is resizable (normally it should
   be), you'll have to put some magic into the Resize event as well. There
   are 4 rules of thumb:

   a. Do not trust the form's height and width properties.  These measure
      the entire form, not the client area where your controls are.  To see
      this in action, create a simple applet with the only code being in
      the resize event which resets a line control from 0,0 to the form's
      width,height properties.  The top left corner is in the client area,
      the bottom right corner disappears.  The API call GetClientRect will
      return the size of the client area in pixels.  You can use the screen
      object's TwipsPerPixelX and TwipsPerPixelY properties to convert from
      pixels to twips. If that's not enough, GetWindowRect will return the
      actual size of the entire form, client and non-client areas combined.
      GetSystemMetrics will return individual pieces of things like border
      width/hight, caption height, etc.

   b. Use the TextWidth and TextHeight properties.  You can use them off
      the form if all your controls share the same font, otherwise use them
      off of the given control.  I typically do a TextWidth("X") and
      TextHeight("X") to get a value which I use as a margin between
      controls.  I grab these values on startup, and multiply it by 2, 1.5,
      .75, .5, .25 to get varying margin sizes, depending on how close or
      far apart I want to space things. If your control has an autosize
      property, you may want to use it, and then calculate the maximum
      width of a control in a given "column" of controls on your screen and
      position all of them accordingly.

   c. Try not to resize your controls in the resize event.  You will spawn
      another resize event in the process.  Of course, you can use a flag
      to determine whether the resize event is the original event or the
      spawned one.  Using the load event, and setting the forms borders to
      fixed minimizes the amount of work you have to do.

   d. Make sure you use a consistant scale.  I don't even bother with the
      scale properties, but instead just convert pixels (from API calls)
      into twips and be done with it.  If you do use scale properties, be
      sure you convert your numbers correctly.  I had no end of difficulty
      when I failed to convert into twips with one number that was used in
      a series of calculations to position controls.  Also be sure all your
      controls share the same SCALE -- another nasty problem I had before I
      gave up on them completely.
      [Thanks to our generous anonymous source "D"]

22.How do I do Peek and Poke?

   VB provides no mechanism for this.  There are several 3rd party pkgs.
   which provide this.  Also, this often comes up in regards to the comm
   ports and you can many times do what you want with the mscomm.vbx.
   [George Tatge (gat@csn.org)]

   Rumours has it than one of MicroHelp's freeware (not crippleware) DLLs
   had this capability. Any details, anyone?

   There's a shareware package for in/out routines, btw.

23.Why doesn't "my string" & Chr$(13) do what I want?

   You need to also add a Chr$(10):  "my string" & Chr$(13) & Chr$(10) will
   give you a CR and LF.
   [George Tatge (gat@csn.org)]

24.How do I prevent multiple instances of my program?

   In VB 3, the property App.PrevInstance is set to True if an older
   instance of the program already exist.

   The following piece of code, stolen from MS KB article Q102480, will
   activate the old instance and then terminate itself:

     Sub Form_Load ()
       If App.PrevInstance Then
          SaveTitle$ = App.Title
          App.Title = "... duplicate instance."      'Pretty, eh?
          Form1.Caption = "... duplicate instance."
          AppActivate SaveTitle$
          SendKeys "% R", True
          End
       End If
     End Sub

   As Robert Knienider(rknienid@email.tuwien.ac.at) informed me, this piece
   of code WILL NOT work for non-English versions of MS Windows where the
   word for "Restore" does not have "R" as the underlined word. Replace the
   "R" in the SendKeys line above with "{ENTER}" or "~".

   Note that you shouldn't prevent multiple instances of your application
   unless you have a good reason to do so, since this is a very useful
   feature in MS Windows. Windows will only load the code and dynamic link
   code *once*, so it (normally) uses much less memory for the later
   instances than the first.

25.How do I implement an accelerator key for a text box?

   You want to use a label caption to identify a text box and to act as if
   it were the text box caption:

   Example:

   &Label1  [text1      ]

   How should I do to set the focus to text1, by typing <ALT>L

   Make sure that the TabIndex property for the text box is 1 greater than
   the
   label's TabIndex. Since a label can't have the focus, the focus will go
   to the next item in the tab order, which would be the text box.

   Here's any easy way to set the TabIndex for a busy form. Select the
   object that should be last in the tab order and then select the TabIndex
   property. Press 0 (zero), click on the next to last object, press 0,
   click on the  the next object back, press 0, etc.  When you're done, all
   of the TabIndexes  will be in order, because VB increments all of the
   higher TabIndexes when you put in a lower number.

   Many thanks to Jonathan Kinnick and Gary Weinfurther that provided the
   answer
   on the FIDO net echo VISUAL_BASIC.
   [Tiago Leal (Tiago.Leal@p25.f1.n283.z2.gds.nl)]

26.How do I force a file dialogue box to reread the currect disk?

   If you make a simple dialogue box modelled after common dialogue
   (normally you should *use* the common dialogue VBX!), you will notice
   that reselecting the diskette drive will not really rescan the disk.
   Very annoying to change to C:, and to reselect A: just to make it read
   the directory of a new diskette.

   To solve this problem, put

     drive1.refresh

     dir1.refresh
     file1.refresh

   in the code for the "Rescan" button (or whatever).

27.How do I get the number of free bytes on a disk? [**]

   See Article Q113590 (or Q106553) in Microsoft's VB KnowledgeBase. A
   short extract follows:

   Declare Function DiskSpaceFree Lib "SETUPKIT.DLL" () As Long

   Dim free_space& ' Holds number of bytes returned from DiskSpaceFree().
   ChDrive "c:"    ' Change to the drive you want to test.
   free_space& = DiskSpaceFree()
   [Geir Tutturen(itfgt@nlh10.nlh.no)]

28.Data Control missing from toolbox when I use VB under NT 3.5. Huh? [**]

   Open the VB.INI file and add these lines under the [Visual Basic]
   heading:

   ReportDesign=1
   DataAccess=1
   [Danny Ames (dames@pic.net)]


D. ADVANCED VISUAL BASIC PROGRAMMING ISSUES


1. How do I tell when an application executed using the SHELL command is
   finished?

   Shell() doesn't really return a task handle, it returns an instance
   handle. Any documentation that says otherwise is wrong. But never mind
   that; the answer to your question is to use the API call GetModuleUsage.

     'Put this in the general declarations of your form/module
     Declare Function GetModuleUsage Lib "Kernel" (ByVal
     |hModule As Integer) As Integer

     'Here's where you shell out to the other program
     intHandle = Shell("PROGRAM.EXE")
     Do While GetModuleUsage(intHandle) > 0
        DoEvents
     Loop
   [Kenn Nesbitt, Microsoft Consulting Services (kennn@netcom.com)]

   The FindWindow command can also be used (search the Tips help file for
   "How VB Can Determine if a Specific Windows Program Is Running"). I have
   had to use this when the program I shelled to unloaded itself and ran a
   different EXE. My program thought the shell was done (since the shelled
   EXE ended), but it really had just "moved on" to another EXE. Generally,
   the code in cases like this must be customized to fit the situation.
   [John McGuire (jmcguire@jax.jaxnet.com)]

2. How do I access C style strings?

   Use the 'lstrlen' and 'lstrcpy' calls found in the Kernel DLL.

3. How can I change the printer Windows uses in code without using the
   print common dialog? How can I change orientation? [++]

   You can change the printer the VB 3.0 Printer object is pointing to
   programmatically (without using the common dialogs). Just use the
   WriteProfileString API call and rewrite the [WINDOWS],  DEVICE entry in
   the WIN.INI file!  VB will instantly use the new printer, when the next
   Printer.Print command is issued. If you get the old printer string
   before you rewrite it (GetProfileString API call), you can set it back

   after using a specific printer. This technique is especially useful,
   when you want to use a FAX printer driver: Select the FAX driver, send
   your fax by printing to it and switch back to the normal default
   printer.
   [Hajo Schmidt (hajo@bwl.bwl.th-darmstadt.de)]

   It is recommended (and polite, as we're multitasking) to send a
   WM_WININCHANGE (&H1A) to all windows to tell them of the change. Also,
   under some circumstances the printer object won't notice that you have
   changed the default printer unless you do this.

     Declare Function SendMessage(ByVal hWnd As Integer,
     |ByVal wMsg As Integer, ByVal wParam As Integer,
     |lParam As Any) As Long
     Global Const WM_WININICHANGE = &H1A
     Global Const HWND_BROADCAST = &HFFFF
     ' Dummy means send to all top windows.

     ' Send name of changed section as lParam.
     lRes = SendMessage(HWND_BROADCAST, WM_WININICHANGE, 0,
     |ByVal "Windows")
   [Nic Gibson (nic@skin.demon.co.uk)]

   To change between landscape and portrait orientation, search of VBKB_FT
   on "lands*" finds Article ID: Q80185 "How to Set Landscape or Portrait
   for Printer from VB App".

   This is an extract:

     Declare Function Escape% Lib "GDI" (ByVal hDC%, ByVal nEsc%, ByVal nLen%,
       |lpData As Any, lpOut As Any)

     Sub Command1_Click ()
        Const PORTRAIT = 1
        Const LANDSCAPE = 2
        Const GETSETPAPERORIENT = 30
        Dim Orient As OrientStructure
        Printer.Print ""
        Orient.Orientation = LANDSCAPE
        x% = Escape(Printer.hDC, GETSETPAPERORIENT, Len(Orient), "", Null)
        Print x%
     End Sub
   [Ayn Shipley (ashipley@hookup.net)]

4. Any tips for speeding up VB?

   Who said "code in C"???? ;-)

   a. When SHOWing a form with lots of bound controls, have a blank frame
      covering everything. Then, in the Form_Activate event, set the
      Frame.Visible = False. This greatly speeds the display of the form
      and hides ugly thrashing as the data controls initialize.
      [Christopher Biow (biow@cs.umd.edu)]

   b. Try to keep any Global definitions to a minimum.  Massive numbers of
      global variables really seem to slow VB Windows down (besides chewing
      up memory).  In other words, if you've pasted a lot of stuff from the
      globals.txt file, trim all definitions and variables you don't use in
      your application.

   c. Keep the total number of controls and forms used to a minimum (you've
      probably already guessed that).

   d. Keep fancy graphics to a minimum (another one you know).

   e. Try "pre-processing" in the background (using Do_Events).  Doesn't
      really speed anything up, but often there is a lot of "idle" time
      while the user is selecting menu's, buttons and such - if you can do

      some calculations, image loading or whatever during this idle time
      your user perceives the application is faster than it really is.

   f. Hide often-used forms rather than unloading them. Unloading saves
      memory, but it takes longer to re-load a form than to simply "un-
      hide" it.
      [Tips b to f by Galen Raben (galenr@gr.hp.com)]

   The following tip is along the same lines, but with a code sample. They
   are provided by Andy Dingley (dingbat@codesmth.demon.co.uk):

   You're limited by the system as to how quickly you can go from calling
   frmMyForm.Show to being able to type into the controls, but you can make
   the form *appear* to display faster. One technique is to keep forms
   loaded, and just switch their visibility on and off. This is heavy on
   resource usage, and doesn't help for the first time they're shown.

   Most forms have some processing (eg. querying a table to fill a list
   box) that goes on when they're first opened, and this is what causes the
   most serious delay. It's possible to display the form, make its controls
   appear on screen, then do the slow processing before finally making the
   form "live". As the user can see things happening, the perceived delay
   is less obvious.

   Include the following code in your form:

     Option Explicit
     Dim FirstActivation as integer

     Sub Form_Activate
        DoEvents   'Allow the _Load event to be seen on screen
        If FirstActivation Then

           ' Do all the slow loading stuff here
           If FillComboBox <> 0 Then
              Unload Me 'If it all goes horribly wrong, then you
                        'can call Unload from an _Activate event
                        '(Which you can't do from the _Load event)
           End If
           FirstActivation = False
        End If
        Screen.MousePointer = DEFAULT
     End Sub

     Sub Form_Load
        FirstActivation = True
     End Sub

   Show the form by using:

     Screen.MousePointer = HOURGLASS
     frmMyForm.Show MODAL


   Bruce Garrett (bruceg@access2.digex.net) had the following tips from his
   VBITS 93 notes:

   - Polling a control for its properties directly is 10 to 20
     times slower then placing the property values you need into
     variables and testing the value of the variables.

   - Swap tuning: Modules are not loaded until used; put related
     code in the same modules, reduce the number of intermodule
     calls and keep modules small.

   - Binary file I/O is faster then Text/Random.

   There was also a lot of discussion about "apparent" speed i.e: how it
   looks on the screen as opposed to how fast it's chugging internally. It

   was noted that the cute little flashing menu items and exploding windows
   in the Mac amounted to a little razzle-dazzle to distract you from how
   long it took to actually load something and get it on the screen.
   Keeping all your forms loaded but hidden until needed was suggested.
   Also the use of progress indicators and a simple quickly loaded and
   drawn startup form. Also preloading data you expect to need.

5. How do I speed up control property access?

   Instead of using a property in a loop, you will be better off using a
   normal variable in the loop and then assign the variable once to the
   property afterwards. Also, when reading a property, you should read it
   once into a variable instead of using it in a loop.

   Sometimes it is not possible to simply put contents of a property into a
   variable. For example, if you are using a list box or you need to
   conserve memory. In these cases you can send the WM_SetRedraw message to
   the control to prevent redrawing. You can typically increase the speed
   6-10 times - or even more.

     'Add the following declares:
     Declare Function SendMessage Lib "User" (ByVal hWnd As
     |Integer, ByVal wMsg As Integer, ByVal wParam As
     |Integer, lParam As Any) As Long
     Const WM_SetRedraw = &HB

     'Add this to your code:
     Result% = SendMessage(Text1.hWnd, WM_SetRedraw, 0, 0)
     'redraw off
     'Do your stuff here!
     Result% = SendMessage(Text1.hWnd, WM_SetRedraw, 1, 0)
     'redraw on

   This same method applies to list boxes and other controls.

6. How much gain in performance will I get if I write my number crunching
   routines in C instead of Visual Basic?

   Probably the best solution to the number crunching problem is to write
   the number crunching routines as a custom control or a DLL, and plug it
   into a VB app. VB interface handling is not significantly slower than,
   say C++, and most of the wait is associated with Windows.

   Some real world experience speaks volumes about this one:

   I wrote some time consuming code in VB to solve a combinatorical (does
   this word exist in English?) problem. The code consists of one main
   recursive function, which calls itself very often. It took a night to
   compute a certain problem. I was rather disappointed and then decided to
   write the central routine in C++. It was a 1:1 transcription. The
   routine was compiled with the MS C++-Compiler. It took only 22 Minutes
   for the same problem. Amazing, isn't it? The routine doesn't do any
   floating point arithmetic, only integer, and handles some arrays. The PC
   was a 33MHz 486. And the second amazing thing is, that a IBM RS6000
   (560)-Risc-machine needed 17 Min for the same code. I was the only one
   on the machine. I thought it should be much faster. The MS C++ seems to
   make very fast, optimized code. The optimization was configured to make
   fast code.
   [Christoph Steinbeck (steinbeck@uni-bonn.de)]

7. How do you make a TEXTBOX read only? Or, how do I prevent the user from
   changing the text in a TEXTBOX?

   There's a lot of ideas on this one. You can grab the _KeyPress and
   _KeyDown events and set them to zero. However, the best idea is to use
   the Windows API SendMessage function to tell the control to become read-
   only:

     'After making the following declarations...

     Global Const WM_USER = &H400
     Global Const EM_SETREADONLY = (WM_USER + 31)
     Declare Function SendMessage Lib "User" (ByVal hWnd As
     |Integer ByVal wMsg As Integer, ByVal wParam As
     |Integer, lParam As Any) As Long

     'Then Try:
     SendMessage(Text1.hWnd, EM_SETREADONLY, 1, 0)
     [Pete Jones (pjones@csi.compuserve.com)]

   This will still allow the user to copy *from* the text box. If you need
   to disable this (why?), steal the Ctrl-C in the _KeyPress event.

8. How can I create a VBX?

   VBXs (Visual Basic eXtensions) are practically always written is C
   (Borland C++, but mainly MS VC++). You should refer to the _Control
   Development Guide_ (in VB Professional Features Vol. I) and any relevant
   documentation for your compiler. Followup questions should normally be
   directed to comp.os.ms-windows.programmer.* or comp.lang.c*.

   There are some example VBX's with C code supplied with VB3 Pro. You'll
   find them under the directory [VB]\CDK.

9. How do you change the system menu (on the Control-Menu Box)?

   You can turn off the minimize and maximize menu options by changing
   properties, but what if you need to remove the "close" option?

     'Make the following declares.
     Declare Function GetSystemMenu Lib "User" (ByVal hWnd
     |As Integer, ByVal bRevert As Integer) As Integer
     Declare Function RemoveMenu Lib "User" (ByVal hMenu
     |As Integer, ByVal nPosition As Integer, ByVal wFlags As
     |Integer) As Integer
     Global Const MF_BYPOSITION=&H400

     'Use the following code to remove the "close" option.
     SystemMenu% = GetSystemMenu (hWnd, 0)
     Res% = RemoveMenu(SystemMenu%,6, MF_BYPOSITION)
     '(also remove the separator line)
     Res% = RemoveMenu(SystemMenu%,6, MF_BYPOSITION)

   Adding menu items to the control menu is more complicated, since you
   need to respond to the events triggered when the user selects the new
   options. The newest Message Blaster (msgblast.vbx, see details in
   beginning of FAQ about how to get files) contains example code.

10.How do I play MID, WAV or other multimedia files? [++]

   Use the MSMCI.VBX, provided with VB/Win Pro 3.0. You can also declare
   and call the MM-functions manually:

     Declare Function mciExecute Lib "MMSystem"
     |(ByVal FileName as String) As Integer

     Sub Form1_Click ()
         iResult = mciExecute("Play c:\windows\mkmyday.wav")
     End Sub

   Also:

   Playing a WAV file is covered in the VB Tips help file (there is a
   Windows call that is for this specificially; see below). The routine
   won't play MIDI files or other sound formats, however.

   Declare Function sndPlaySound Lib "MMSYSTEM.DLL"
    |(ByVal WavFile$, ByVal Flags%) As Integer
   Global Const SND_SYNC = &H0

   Global Const SND_ASYNC = &H1
   Global Const SND_NODEFAULT = &H2
   Global Const SND_LOOP = &H8
   Global Const SND_NOSTOP = &H10
   Global Const SND_USUAL = SND_ASYNC And SND_NODEFAULT
   [John McGuire (jmcguire@jax.jaxnet.com)]

11.How can I call a 'hidden' DOS program from VB?

   If you run a DOS program minimized using the SHELL command, it will
   never complete. This is because DOS tasks by default are NOT setup to
   run in the background. The easiest way to get around this is to make a
   PIF file for the program you need to run with the "Background" option
   checked. Then SHELL to the PIF file to run the DOS program and it will
   return control to your VB application when it terminates.

   Tip: If you edit or replace the _DEFAULT.PIF file in the Windows
   directory to allow execution in background, this will apply to all DOS
   boxes that is not run with it's own .pif!

12.How do I do drag & drop between applications?

   MSGBLAST.ZIP (the famous Message Blaster by Ed Staffin and Kyle Marsh)
   available on Cica and mirrors tell you *everything* you want to know
   about this and other advanced stuff. This is now (inexpensive)
   shareware, but the older freeware version is still supposed to be
   available. Get the file mentined above for more info.

   Short glossary for the confused ones  :-)
   Drag & Drop Client: the form you drop objects to/on
   Drag & Drop Server: the form you drag object(s) from

13.How do I use GetPrivateProfileString to read from INI files?

   There's a good example of accessing *.INI files in the Knowledge Base,
   but here's the basic idea:

     'You declare these API function as usual:
     Declare Function GetPrivateProfileString Lib "Kernel"
     |(ByVal lpApplicationName As String, ByVal lpKeyName
     |As Any, ByVal lpDefault As String, ByVal
     |lpReturnedString As String, ByVal nSize As Integer,
     |ByVal lpFileName As String) As Integer

     'Then in your code you do like below:
     strIniFile = "WIN.INI"
     strSection = "MyProgram"
     strKey = "Language"
     strDefault = "English"
     iLength = 70
     strReturn = String$(iLength, " ")  'Pad the string first!
     iResult = GetPrivateProfileString(strSection, strKey,
     |strDefault, strReturn, iLength, strIniFile)

   WARNING: Be aware that there was an ERROR in the Windows 3.1 API
   documentation that came with VB. Here's the scoop:

   Knowledge Base article Q110826 (DOCERR: GetPrivateProfileString
   Declaration Incorrect in API) corrects a documentation error for the
   GetPrivateProfileString function call as described in the Windows
   version 3.1 API Reference help file that shipped with Microsoft Visual
   Basic version 3.0 for Windows. The CORRECT declaration is as follows:

     Declare Function GetPrivateProfileString Lib "Kernel"
     |(ByVal lpApplicationName As String, ByVal lpKeyName
     |As Any, ByVal lpDefault As String, ByVal
     |lpReturnedString As String, ByVal nSize As Integer,
     |ByVal lpFileName As String) As Integer

   Note that the "ByVal" keyword was omitted from the second parameter in
   the online reference. This means that the function is passing the second
   parameter (lpKeyName) by reference. It needs to be passed by value.

   The most common problem that occurs when using the incorrect declaration
   is that when the function is called, it returns a copy of "lpdefault" in
   the "lpReturnedString" parameter instead of the actual value referenced
   by KeyName.

   OOPS: As P. Wierenga (pwiereng@sol.UVic.CA) told me, the same doc error
   applies to Writeblablabla:

   DOCERR: WriteProfileString Declaration Incorrect in API Article ID:
   Q115328

   The correct declaration is as follows:

     Declare Function WritePrivateProfileString Lib "Kernel"
                                      (ByVal lpApplicationName As String,
                                       ByVal lpKeyName As Any,
                                       ByVal lpString As Any,
                                       ByVal lplFileName As String) As Integer

   (all on one line of course!)


14.How do I implement Undo?

   For most controls, you will have to keep track of changes yourself.
   There's no magic involved, just some coding. However, if you use the
   standard Text box or Combo box, Windows provides a "free" undo function
   for you!

     'Do the following declares:
     Declare Function SendMessage Lib "User" (ByVal hWnd As
     |Integer, ByVal wMsg As Integer, ByVal wParam As
     |Integer, lParam As Any) As Long
     Global Const WM_USER = &h400
     Global Const EM_UNDO = WM_USER + 23

     'And in your Undo Sub do the following:
     UndoResult = SendMessage(myControl.hWnd, EM_UNDO, 0, 0)
     'UndoResult = -1 indicates an error.

15.How do I create a window with a small title bar as in a floating
   toolbar? [++]

   Download the MSGBLAST VBX from ftp.microsoft.com (filename msgblast.zip)
   or (better) from ftp.cica.indiana.edu or mirrors. The example files
   provide an example of a form with a small title. When you see it, you'll
   understand why I haven't include a full explanation here!

16.What is Pseudocode?

   VB/Win does not generate machine code like most compilers do. Instead it
   creates what is called pseudocode (a real misnomer, IMO). A good
   explanation is given below:

   A bit of history: the original P-code was an instruction set for a
   "virtual Pascal" machine. This came with a portable Pascal compiler
   written at ETH in Zuerich. The portable compiler produced instructions
   for this phony machine which had an instruction set ideally suited to
   the stack and heap management of Pascal.  To executed portable Pascal
   programs, you had two choices: either write an interpreter for P-code,
   or translate the small set of P-code instructions (there were about 80)
   into assembler; assemble it; and run it at native speed.  Thus "P-code"
   originally stood for "Portable" or "Pascal" code. The broader meaning,
   "pseudo-code" came later. P-code was widely popularized by the UCSD
   Pascal system, a small workstation that was implemented entirely in

   Pcode and interpreted. It was sold for some years, and one company even
   re-did the microcode for a PDP-11 microchip to interpret P-code. The
   original Borland Turbo Pascal had obvious similarities to the UCSD
   system although it was not interpreted. The dialect was virtually
   identical.  Today P-code is used extensively in Microsoft apps, for two
   reasons. First, it is much more compact than  native code; so the apps
   are smaller. Second, having an interpreter at the core of an app makes
   it much easier to customize and extend. That is why VB is becoming the
   heart of the MS major apps.  It is simply not true that P-code apps run
   much slower than native apps. The slowdown is determined by the
   granularity of the interpreted routines. If every little thing is an
   interpreted op, the slowdown might be as much as 3-to-1 for the 80x86
   architecture, or about 2-to-1 for the Motorola 68000 family (which is
   better suited to writing interpreters).  But in practice, modern P-code
   systems have large-scale instructions, each of which is executed by a
   big compiled subroutine. These subs run at native speed, so the overhead
   of the interpreter is occasional at worst.
   [Roger E. Ison (r_ison@csn.org)]

   It is also possible that since the code may not need recompilation to
   run on other platforms *if* the run-time interpreter is first ported, VB
   applications can become very portable. This depends on Microsoft's long-
   term plans.

   A note on the word "pseudocode": I wrote above that it is a misnomer,
   and I stand on that. Pseudocode is *really* the pascal-like (mostly)
   explanation of an algorithm that is intended for human readers, not
   computers. But since somehow the term pseudocode stuck to the psaudo-
   machine-code created by VB the word is used here.

17.Does VB support pointers to functions?

   No, it does not.
   [George Tatge (gat@csn.org)]

18.How do I program the Novell NetWare API from VB?

   Tom Tregilgas (Tom.Tregilgas@InfoB.unisg.ch) had a lot of information on
   this one. Normally I leave it to the other FAQ parts to list books &
   how-to-get-info's, but since this topic is very specific and more
   NetWare than VB I include all the stuff here for your convenience:

   If you are interested in seeing how Visual Basic can be used for
   NetWare programming, obtain the following files from your friendly
   neighboorhood Novell FTP Mirror site.

   Mirror sites are (according to ftp.novell.com):

         Novell Germany            ftp.novell.de
         Netherlands               ftp.rug.nl
         United Kingdom            ftp.salford.ac.uk
         Logan, Utah               netlab2.usu.edu
         New Zealand               tui.lincoln.ac.nz
         Tuscaloosa, Alabama       risc.ua.edu
         Ottowa, Ontario, CA       novell.nrc.ca
         Boston, Mass              bnug.proteon.com

   novlib\11\nivb.zip              Netware Interface for Visual Basic
   novlib\11\nwtest.zip            NetWare Test for Visual Basic

   There are also two Novell App Notes on the subject of using NetWare with
   Visual Basic (although this is _NOT_ supported by Novell...) which are:

   October 92      Interfacing Visual Basic for Windows and NetWare
   July 93         A NetWare Interface for Visual Basic

   The AppNotes can be obtained by contacting the Novell Research Order
   Desk, FAX: +1 303 294-0903, Voice 800 377-4136, +1 303 297-2725.
   Address as follows:


   Novell Research Order Desk
   1601 Park Avenue West
   Denver, CO 80216-5199

   AppNotes are $95/year ($135 outside US)

   Here are a few books which might help you out to figure the calls out:

   Windows Development on NetWare Systems, Lori Gauthier and Sue Whitehead
   (c) 1994, Windcrest, Blue Ridge Summit, PA 17294-0850 (McGraw-Hill)
   $34.95 Comes with disk This book also tells you how to "upgrade" to the
   currently supported SDK calls

   NetWare System Interface Technical Overview, Novell (c) 1990,1989
   (Addison-Wesley), $32.95 (describes Novell's C Network Compiler API's)

   Visual Basic Programmer's Guide to the Windows API, Daniel Appleman
   Ziff-Davis Press, 5903 Christie Ave, Emeryville, CA 94608, $34.95  Comes
   with disk

   It should be mentioned that the APIs included with the NIVB are _not_
   current, and for this purpose, you should get the Novell SDK kit. Also,
   Novell will not support NIVB, but you can sometimes get some helpfrom
   Compu$erve, or from others on the Infobahn <g>

   Good luck!

   p.s. It behooves you to become a member in the PDP (Professional
   Developer's Program) since you get the AppNotes (& Bullets!) for...free.

   p.p.s. Novell does NOT support the NIVB...

   p.p.p.s. Also, no docs come with it.  You'll probably need the Client C
   SDK kit to be able to really _use_ the code.

   p.p.p.p.s. To make things even better, the calls in NIVB are fairly old,
   and not of the Client C SDK kit variety.  However, there _are_ books
   which could help you out, e.g. "NetWare System Interface Technical
   Overview", by Novell. ISBN:0-201-57027-0, published by Addison-Wesley
   Publishing co, $32.95 US, $42.95 in Canada.

   Update:

   AppNotes are dead, however, Develper Notes live on.  There is one
   article about NetWare programming with Visual Basic here:

   July/Aug 94     NetWare Programming in Visual Basic:
                   Using Apiary's NetWare Client SDK for Visual Basic

19.Some Visual Basic 4 rumours

   First, we have no special information. This is just rumours, guessing,
   gossip! But since there are many questions about this on the newsgroup,
   *and* Microsoft gives these controlled leakages through their beta
   testers, we bring on some of it (Please, don't start discussing NDA's on
   this group again!):

   a. Two versions: 32-bit and 16-bit
      Like Visual C++ 1.5, VB 4 will come with compilers for the 16-bit API
      from Windows 3.1 as well as a real 32-bit compiler (or
      pseudocompiler) for Windows 4 (Chicago) bundled together.

   b. New features will probably be inherited from VBA

      1)   Line continuation character " _" (space+underscore)

      2)   WITH statement, known from Pascal, to save typing and make code
           cleaner. An example:


             With Form1
               With Text1
                 Bold = true
                 FontName = "New Times Roman"
               End With
             End With

      3)   FOR EACH .. NEXT statement allows you to make changes to a group
           of objects at once better than FOR..NEXT. Object groups are also
           something you may have to work closer with in VB4.

      4)   An OPTIONAL statement allows you to leave some Variant
           parameteres undefined when calling a user-defined sub or
           function. Also in VBA is an ARRAY function that returns an array
           form a list supplied as parametres, and a special optional
           ParamArray optional parameter of Variants.

      5)   Boolean data type. Integer does the job, but this type can
           preserve space if Microsoft codes it right.

      6)   Byte data type? No, VBA does not support this. We can dream,
           however.

   c. VBX is dead. Long live OCX!

      You may not feel for celebrating this either, but the 32 bit VB 4
      will not support the old 16-bit VBX'es. The 16-bit version of VB 4
      will support them for backwards compatibility, but be aware that OLE
      2 and OCX is the way of the future, at least if Microsoft gets it as
      they want.

20.How do you change the icon and otherwise manipulate the DOS box? [**]

   Enclosed is the results of my digging around to enable me to change the
   icon of a DOS box launched with the SHELL function. It illustrates most
   aspects of dealing with DOS boxes.

   Example of launching PIF file minimized and running it in the
   background (Needs Execute Background box checked in PIF file), and
   assigning the PIF file a new Icon rather than the default DOS Box Icon.

   (Note: it seems this method changes the icon of ALL the active DOS
   boxes)

   Code follows:
   x---------------------------------------------------------------------x
     Option Explicit

     Global Const SWP_NOSIZE = 1
     Global Const SWP_NOMOVE = 2
     Global Const SWP_NOACTIVATE = &H10
     Global Const SWP_SHOWWINDOW = &H40
     Global Const SWP_HIDEWINDOW = &H80
     Global Const SWP_FLAGS = SWP_NOMOVE Or SWP_NOSIZE Or SWP_NOACTIVATE
     Global Const SWP_SHOW = SWP_SHOWWINDOW Or SWP_FLAGS
     Global Const SWP_HIDE = SWP_HIDEWINDOW Or SWP_FLAGS
     Global Const HWND_BOTTOM = 1
     Global Const GCW_HICON = (-14)
     Global Const GCW_HMODULE = (-16)

     Declare Function GetModuleUsage Lib "Kernel" (ByVal hWnd%) As Integer
     Declare Function ExtractIcon Lib "Shell" (ByVal hInst%,
     |ByVal lpExeName$, ByVal hIcon%) As Integer
     Declare Function DestroyIcon Lib "User" (ByVal hIcon%) As Integer
     Declare Function FindWindow Lib "User" (ByVal lpClassName As Any,
     |ByVal lpCaption As Any) as Integer

     Declare Function SetWindowPos Lib "User" (ByVal h%, ByVal hb%,
     |ByVal X%, ByVal y%, ByVal cx%, ByVal cy%, ByVal F%) as Integer
     Declare Function GetClassWord Lib "User" (ByVal hWnd%, ByVal nIndex%)
     |As Integer
     Declare Function SetClassWord Lib "User" (ByVal hWnd%, ByVal nIndex%,
     |ByVal wNewWord%) As Integer

     Sub LaunchPif(PifFile as String, IconName as String)
         Dim Res As Integer     'Return value from API call
         Dim MyInst As Integer  'Instance handle for this app
         Dim PifIcon As Integer 'Pif Icon Resource name
         Dim OldIcon as Integer 'Original Pif Icon resource (default = 0)
         Dim PifhWnd As Integer 'Dos Box Window handle
         'Launch PIF file
         PifInst = Shell(PifFile, 6)
         'Get Instance handle for main MDI Window (assumed to be frmMDI)
         MyInst = GetClassWord((frmMDI.hWnd), GCW_HMODULE)
         'Create new Icon resouce by loading Icon from disk file
         'Check Icon file exists
         If Dir$(IconName) <> "" Then
            'Make sure string is null terminated
            IconName = IconName & Chr$(0)
            'Create Icon resource in this window
            PifIcon = ExtractIcon(MyInst, IconName, 0)
         Else
            PifIcon = 0
         End If
         'Reset Default Icon on DOS Box to PifIcon
         'Check PIF file still running and Icon resource created
         If GetModuleUsage(PifInst) <> 0 and PifIcon > 0 Then
            'Get Pif Window handle
            PifhWnd = FindWindow(0&, "Window name in PIF file")
            'Set Icon handle to PifIcon resource
            OldIcon = SetClassWord(PifhWnd, GCW_HICON, PifIcon)
            'Hide and show window to get a redraw of the Icon
            Res = SetWindowPos(PifhWnd, HWND_BOTTOM, 0, 0, 0, 0, SWP_HIDE)
            Res = SetWindowPos(PifhWnd, HWND_BOTTOM, 0, 0, 0, 0, SWP_SHOW)
         End If

         'Wait for PIF file to complete
         Do While GetModuleUsage(PifInst) <> 0
            DoEvents
         Loop

         If PifIcon > 0 then
            'Reset Icon to original
            Res = SetClassWord(PifhWnd, GCW_HICON, OldIcon)
            'Tidy up by removing PIF Icon resource
            Res = DestroyIcon(PifIcon)
         Endif
     End Sub
   x---------------------------------------------------------------------x
   [Dr David Baird (BairdD@AgResearch.CRI.NZ)]

21.How do I make the mouse cursor invisible/visible? [**]

   Use the API call ShowCursor(False) or ShowCursor(True). Just be aware
   that the Windows cursor is a shared object, so if your process hides it
   then it must also redisplay it as well. Also the function is not truly
   "True" or "False" in nature - it is LIFO, so that if your process has
   for some reason set it "False" multiple times then you must set it
   "True" the same number of times in order to re-display the cursor. Hard
   to explain but play with it - you'll see what I mean...
   [Galen Raben (galenr@hpgrla.gr.hp.com)]

22.How do I create controls dynamically (at run-time)? [**]

   Search of VBKB_FT on "control* near array*" finds a number of articles,
   including Article ID: Q79029 "Creating Nested Control Arrays in Visual

   Basic" This is THE article to read to understand control arrays (plus a
   number of other neat concepts). In particular, look at the procedure
   "loadall_click".

   The key is that you need to create the first instance of your_control
   (ie. your_control(0)) at design time.
   [Ayn Shipley (ashipley@hookup.net)]

23.How do I set the Windows wallpaper at runtime? [**]

   I'm surprised this isn't in the FAQ yet. [ED: now it is!} You need the
   SystemParametersInfo API function and the SPI_SETDESKWALLPAPER constant.

   For this you will need the following constants and function
   declaration...

     Const SPI_SETDESKWALLPAPER = 20
     Const SPIF_SENDWININICHANGE = &H2
     Const SPIF_UPDATEINIFILE = &H1
     Declare Function SystemParametersInfo Lib "User" (ByVal uAction As
      |Integer, ByVal uParam As Integer, lpvParam As Any, ByVal fuWinIni As
      |Integer) As Integer

     'You then call the function as follows...

     Result% = SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, ByVal BMPFile$,
      |SPIFlags%)

     '... where SPIFlags% is 0 if the change is not to be made permanent, or
     '(SPIF_UPDATEINIFILE Or SPIF_SENDWININICHANGE) if it is to be carried across
     'into future Windows sessions.

   NOTE: Please be certain to include the ByVal keyword before the bitmap
   filename, as this argument is declared as Any, NOT as ByVal String.
   [Luke Webber(webber@werple.apana.org.au)]


E. CALLING THE WINDOWS API AND DLLs IN GENERAL


1. What is the Windows API?

   The Windows API (Application Program Interface) is a collection of
   Dynamic-Link Libraries (DLLs) that do most of the common things in
   Windows. Calls to the Windows API gives you access to routines that do
   things like drawing menu bars, manipulating bitmaps, playing sound
   files, and pretty much every other function of Windows.

2. How do I call a DLL?

   Basically, you declare a DLL procedure which you can call in your VB
   program which in turn passes data to and/or retrieves data from the DLL.
   You should read the section of the VB manual that talks about calling
   DLLs ("Chapter 24  Calling Procedures in DLLs" in the VB 3.0
   Programmer's Guide). This chapter covers the basics of using the Windows
   API DLLs and calling DLLs in general. Beyond that you may want to find a
   good book on this subject since it is too large to cover here (see the
   Book Listing in the Appendix of the General FAQ - Part 1). Don't be too
   intimidated!  Using DLLs (especially many of the Windows API functions)
   is quite easy, once you learn how to call them. In fact, many of the
   newer DLLs include VB-compatible modules!

3. What about DLL calls that require callbacks?

   VB does not support callbacks, but various extensions can help.

   Dan Appleman's "Visual Basic Programmer's Guide to the Windows API"
   comes with a floppy disk which code samples and tools. It also includes
   a VBX which supports the callbacks which many API calls require. Dan is

   also founder and president of Desaware which sells more extensive tools,
   including SpyWorks, for VB developers.
   [Walter Hill (whill@netcom.com)]

4. Tips for calling DLLs (such as the Windows API)

   a. Using the BYVAL keyword is critical. Using it when you're supposed to
      call by reference and (more common) not using it when you are to give
      a value to the external function are the single most common mistakes.
      Wrong calling convention can often result in a General Protection
      Fault (GPF) or, even worse, corruption of another applications' data.

   b. Check return and parameter types. For return types, a C function
      declared as "void" means you use a Sub not a Function.

   c. Initialize strings by padding it to the necessary length! If you pass
      a string that is too short to the API it will happily write past the
      end of the string and possibly corrupt data.

   d. Use Option Explicit. A typing error that results in a bug in the VB
      source will occasionally cause a GPF when you call external code.

   e. It's a jungle out there! Check parameter values as there is no type
      checking outside VB. If you make a mistake, you'll often get a GPF.

   f. Save before you run! You may even need to restart Windows after a
      GPF, since DLL's often aren't unloaded properly. As a second option
      you can check out WPS (Windows Process Status) which is distributed
      with VB/Pro and placed in the CDK directory. This utility allows you
      to kick out any module (EXE, DLL) from memory (shooting yourself in
      the foot if you want to. WPS is a nice way to find out what DLLs are
      actually used, but save your work first!).


F. VISUAL BASIC AND DATABASES


1. Why can't I use an index with my VB accessed database? [++]

   There is a mistake in the docs which says you can set the active index
   for a recordset. You can't. The data control uses the primary key for
   tables and physical order (I think) for dynasets.
   [Nic Gibson (nic@skin.demon.co.uk)]

   NOTE: You can of course set the indexes yourself using code in VB/Pro
   (Table objects), but Data Control's can't. Sorry for the problems this
   possible misunderstanding caused!

   Thanks to John McGuire (jmcguire@jax.jaxnet.com) for clarifying this.


2. "Can't find installable ISAM" or Why does my compiled VB database app
   generate an error when it ran just fine in the design environment? [++]

   You can thank Microsoft for documenting this topic so poorly. When you
   compile your VB database application, you must also have an INI file for
   it which provides the correct pointers to the appropriate database
   drivers. Therefore, if your application is named "INVOICE.EXE", you will
   need to have a properly configured "INVOICE.INI" file in your Windows
   directory. The file, EXTERNAL.TXT, that came with VB should explain all
   about it.

3. Is the Access Engine and Visual Basic Pro good enough for database work? [++]

   That, of course, depends. Generally the answer is "yes", but you may
   need some third-party add-on products.

   These are the major weaknesses of VBPro's database functions:

   a. Limited data controls: No add, delete or search button; no bound list
      box or masked edit control and - the worst - no bound grid!

   b. No run-time query builder ("how good is your user in SQL?") or report
      builder.

   c. No direct advanced control of the Access 1.1 (or 2) Database Engine
      (ie. security, optimization, etc).

   d. SQL us SLOW. Handcoding is much faster (but harder to code)

   The good news is that lots of companies are willing to sell you products
   which address one or more of the above weaknesses.

   Also, if you build a database application with advanced database
   relations, it can be a good idea to build the database itself with
   Access and the front-end with VB.

4. How do you avoid the "Invalid use of null" error when reading null
   values from a database?

   If you try to retrieve a null value (empty field) from a database, you
   will get the error: "Invalid use of Null". Here is one way to get around
   this problem:

   I've worked around this problem with the following code:

     TextBox.Text = MyTest.Fields("TestFld") & ""

   This code converts the Null-Value into an empty string.
   [Ralf Metzing (rmm@dragon.stgt.sub.org)]

5. What is "NULL"?

   Contrary to popular belief, Null is not nothing. It's even less than
   nothing.   8^)

   The VB documentation describes all the horrors of misunderstanding the
   infamous NULL. Since people don't read the documentation, we feel like
   informing that

     If ThisVarIsNull = NULL then DoSomething

   will *always* fail, and the DoSomething can't possibly be executed. You
   *must* use IsNull(ThisVarIsNull) which will return True if the var is
   Null (phew!).

   If you want to find out why someone came to think of this strange value,
   read some relational database theory.

6. How can I access a record by record number? [++]

   Use a counter or index field - or even better, a Bookmark property - for
   this.

   It is *impossible* to ask a relational database system to give you ie.
   "field number 3 in record number 10" since by definition a relational
   database does not have row or column numbers. Databases allowing direct
   access like that is not even remotely relational.

   Access (and therefore, VB) is about as close to a real relational
   database system as you can get.

7. How about Access 2.0 compatibility? [++]

   You need the compatibility layer availability. The file COMLYR.EXE is in
   the MSBASIC library on Compuserve. This file provides all the items
   necessary for compatibility between VB 3.0 and Access 2.0.
   [Fred Griffin (72321.3230@compuserve.com)]


   The file COMLYR.EXE can be downloaded from ftp.microsoft.com. It is
   located in the directory /softlib/mslfiles. (NOTE: A "DIR" in this
   directory is rarely a wise course of action. There is an enormous amount
   of files im /mslfiles.)

8. Tips for VB database programming: [++]


   a. Use Access and QBE. Once it's "working" (even if the parameters are
      hardcoded), then open up View.SQL and copy the stuff from the SQL
      window into your VB code. If you need to insert VB variables, try
      testing this under Access by using parameters instead. They're then
      nice & easy to spot when it comes to converting into VB - I always
      call my parameters "PR_xxxx", so I can just search my VB code for
      this to find any instances that I've missed.

   b. It never works first time. So put an error handler into your VB code
      that copies the contents of SQLStr onto the clipboard, should the
      query fail. Now it's quick & easy to switch back to Access, find a
      scratch query and paste the erroneous SQL into that. It's *much*
      easier to debug a SQL query in Access, after the variables have been
      merged in, than it is to do it blind from VB.

   c. Use carriage returns to break up your SQL. One before each reserved
      word is sensible. They're not significant in SQL. I assume you're not
      stupid enough to put them in the middle of field names -
      unfortunately Debug.Print is!

   d. When merging in the contents of a variable (building a SQL query in a
      VB string), it should *always* be surrounded by an ampersand and 3
      double quotes, or an ampersand and 2 mixed quotes, depending on your
      local conventions:

        SQLStr = SQLStr & "WHERE Username <= """ & Username$ """ "

        or

        SQLStr = SQLStr & "WHERE Username <= '" & Username$ "' "

   e. If you're using dates, then it will *always* be one quote, a hash and
      an ampersand:

        SQLStr = SQLStr & "WHERE Start_Date <= #" &
        |Format$(CutOffDate,"Long Date") & "# "

   f. Another tip with dates is to format them with the long date format,
      not the short date. This is then safe against the transatlantic
      reversal of month & day position.

   g. If you're merging in a field/table name, enclose it in square
      brackets. That way the SQL will still be valid if the variable
      contains spaces:

        SQLStr = "SELECT * FROM [" & TableName$ "] ;"

      When building SQL strings in VB, then you'll often do this on several
      lines, concatenating SQLStr with the new string. If you leave a space
      at the end of every string, then you can guarantee you won't have
      problems with the text from successive lines running into each other.

   h. If you're using Access 1, you'll keep running into the 1024 character
      limit on the length of a SQL string. Keep the table & field names
      short, especially if many JOINs are concerned. Using underscores in
      names is shorter than spaces, as you don't need the extra 2
      characters for the square brackets around them. If your SQL is
      slightly too long, then you'll probably see a "Missing semicolon"
      error, even though the semicolon is obviously there (To you,
      anyway!).

   i. Making a QueryDef is a complicated process that is often slower than
      executing the query ! Don't mess with the .SQL property, as that is
      equally slow (Access needs to do a lot of work to turn SQL into its
      internal query format). Two ways around this: Use ready-built
      queries, written with Access. If you need to merge in values from

      variables, then use a query with parameters. Setting parameter values
      is quick to execute.

   j. If you really need to build SQL on the fly -- you need to build an ad
      hoc query, or to supply table or field names (which can't be done
      with query parameters), then try using:

        database.Execute SQLStr

      As this doesn't build a QueryDef, then it's quick.
      [Tips a to j by Andy Dingley(dingbat@codesmth.demon.co.uk)]

   k. Make sure all Tables, Dynasets, Snapshots, Databases, and other data
      access objects are properly closed before ending the program. As near
      as I can tell, the pointers to these objects are not destroyed if
      your VB program doesn't Close them (including when a program
      crashes). A Microsoft guy did say he can't find anything that
      confirms that they close, but (of course) he wouldn't say for certain
      that they aren't closed. Based on resources after serious crashes
      (that I couldn't walk the program out of by hand), I don't think
      they're automatically closed.
      [John McGuire (jmcguire@jax.jaxnet.com)]

9. How come I get a "No Current Record" error when I use a a Data Control
   on an empty table?

   Well, this is a "feature" courtesy of Microsoft.  KB article Q106494
   explains this in detail.  Basically, the workaround is to add an empty
   record to the table before the user can do anything (or before you try
   to do any Moves on the Table).
   [George Tatge (gat@csn.org)]

10.How can I speed up my VB database application? [++]

   KB article Q109830 gives some hints.  Things you should do include:

   - Use Snapshots when possible.
   - Use transactions whenever possible.
   - Use Dynasets when possible.
   - Use SQL action queries when possible.
   [George Tatge (gat@csn.org)]

   Major Weakness: SQL is SLOW! A hand-coded search (with indices) is MUCH
   faster than an equivalent SQL call, especially with complex search
   criteria. For example:

     SELECT * FROM Table WHERE SSN = '555-33-1234' AND Posted #01-31-95#

   is a lot slower than:

     Table.Index = "SSN"
     Table.Seek "=", "555-33-1234"
     If Not Table.NoMatch Then
       While Not Table.EOF
         If Table("SSN") "555-33-1234" Then
           Table.MoveLast  'Forces an EOF
         ElseIf Table("Posted") #01-31-95# Then
           'Do something
         End If
         Table.MoveNext
       Wend
     End If

   Granted, it is a LOT more code, but I ran a VERY similar query that took
   THIRTY HOURS! The equivalent hand-written code took ELEVEN MINUTES!
   That's 163 times faster! I think basically SQL isn't very good at
   figuring out which indexes to use (I also think I've read something to
   the effect that the newer version, 2.0 or 2.5, IS better at this).
   [John McGuire (jmcguire@jax.jaxnet.com)]

11.How do I get a bitmap picture in a field in an Access database?

   See p.466 of the Visual Basic (3.0) Programmer's Guide. It contains a
   section called "Using Bound Picture Box and Image Controls". Basically
   you have to bind the VB PictureBox to a field in the Access DB, set the
   .Picture property in the PictureBox, and then move to the next record or
   something. VB will then store your picture in Access in a form in which
   it can be retrieved by VB in the future.

   If you store the pictures in Access directly (using Access), VB won't be
   able to read them (using VB 3.0 and Access 1.1).

   You can also store the picture's filename as a text field in the
   database and use LoadPicture() to load that file into the VB PictureBox.
   [Tim Shea (shea@marcam.com)]

12.What is "Reserved Error -1209"?

   You will get a Reserved Error [-1209] ("There is no message for this
   error") when your database is corrupted. Try opening the database using
   MS Access; if it's corrupted you should get the option to repair it.
   [Joe Abley (joe_abley@originuk.demon.co.uk)]

   You should also compact it, after repair. I recommend you add the
   following to your File menu on your main form:

     Case ...

       RepairDatabase Curentdatabasename

     Case ....

       On Error resume next
       Kill "temp.MDB"
       Name  curentdatabasename as "temp.mdb"
       on error goto errcompact
       compactdatabase "temp.mdb", Currentdatabasename
       kill "temp.mbd"
       exit sub

     errcompact:
       msgbox "compaction failed"
       name "temp.mdb" as Currentdatabasename

     Case ...

   [Ayn Shipley (ashipley@hookup.net) , Kym Wilson]

13."Cannot perform operation. illegal.." with Paradox 3.5 table(s)

   Your Paradox table must have a primary key, or it will be read-only no
   matter what you set its properties to.
   [Ayn Shipley (ashipley@hookup.net)]

14.I'm getting error message "Reserved Error [-nnnn] ("There is no message
   for this error")" from Jet Engine 2.0. Huh? [**]

   See the Knowledge Base article Q117900 "Reserved Error Numbers Returned
   by the Jet 2.0 Engine" for a complete list of the new error messages.

   Extract:
   "Jet_Error/Message_String
      -1010 Invalid database ID.
      -1016 Can't have more than 10 fields in an index.
      -1029 Database engine hasn't been initialized.
      -1030 Database engine has already been initialized.
      -1034 Query support unavailable."
   [Ayn Shipley (ashipley@hookup.net)]

15.Why do I get "object not an array" when I try reference the fields of a
   global object variable which I have set to a table? [**]

   VB has a parser bug which makes it difficult to use database objects
   declared in a module from within a form.

   WORKAROUND: Just perform some _method_ on the table object somewhere
   _before_ you try to reference fields. Say in a form-based subroutine
   AAAA_IllBeFirst you have a Tbl.MoveFirst, which is never even executed.
   Then VB suddenly realises what the object is and all is forgiven.

   Credit to Luke Webber and "Joe Foster of Borg".
   [Ayn Shipley (ashipley@hookup.net)]


G. DISTRIBUTING VISUAL BASIC APPLICATIONS


1. What are some tips for using Setup Wizard?

   There were loads of bugs in the setup utilities supplied with VB3. Be
   sure to get the newest version of SETUPKIT (usually called SETUPK.EXE or
   -.ZIP). It is available from the sources listed in the beginning of this
   document, and in the General FAQ.

   Alternatively, if you have the older versions, you may have to manually
   remove the line referring to OLE2UI.DLL in the file SETUPWIZ.INI. See
   later in this document for dates of newest files on ftp.microsoft.com.

   Follow the instructions in SETUPK.TXT exactly. The files actually belong
   in two separate directories. Not placing them correctly can create
   strange and unusual side effects -- none of them good(!)

   Set all involved EXE, DLL and VBX files to Read-Only so that the setup
   program doesn't modify them.
   [Charles F. Mulks (21667cfm@msu.edu)]

   A *very* good tip. Actually, make all executables on your system read-
   only. If not, you can get a sharing violation if you try to run the same
   DOS executable twice at the same time.

   Also, the source code for a SETUP program is *included* with VB3 Pro. It
   is quite trivial to tailor it to your specific needs.

   The question remains: Is SetupWiz good? No! Good enough? Perhaps.

2. Are there restrictions on what I can distribute with my VB program?

   The documentation tells what parts of the Visual Basic kit you can
   freely distribute: the VBX files, some DLL's and what the SetupKit
   includes on your distribution diskettes. Reading software license
   agreements may be more boring than asking the newsgroup, but is
   nevertheless a good idea. 8^)

   There have been some rumours on the newsgroup that you can't
   redistribute programs written with VB freely. This is nonsense. All
   applications created with VB can be redistributed freely without
   royalties (as long as you don't distribute proprietary external files).

   The rumours probably originated when Microsoft announced that they will
   not sell kits allowing third-party software to include the Visual Basic
   for Applications (VBA) system.

3. What alternatives to setup wizard do I have?

   Perhaps the best one is to simply modify the setup app which is supplied
   with VB.  Look in your VB directory for the setupkit\ setup1 directory.
   There you will find everything you need to do a complete setup program.
   This sample setup is coded to install a few sample app files and create

   a program group.  You can comment out those lines and change to your
   files and program mgr. group.  There are also a few global variables you
   will want to change.  All of this is contained in the comments in the
   code.

   Using this, and the distribution information in the manual telling you
   about which files to distribute with your app will make things much
   easier than using the setup wizard (IMNSHO).

   There are also several third party setup products available.
   [George Tatge (gat@csn.org)]

4. Do I need to worry about users who have Progman replacements such as
   Norton Desktop and PC Tools?

   Earlier versions of those products and some others do not respond
   properly to the DLL commands to create groups and items.  More recent
   versions do.  All you can do in this case is to include some information
   in your readme.txt file that instructs users of those products to shut
   them down and start up program manager before installing.
   [George Tatge (gat@csn.org)]

5. Can I distribute my app without vbrunXXX.dll?

   If you are sure that your users have it or can get it, you can easily
   distribute your app without vbrunXXX.dll.  Simply remove the file from
   your distribution disk or zip file and and ALSO remove it from the
   setup.lst file.
   [George Tatge (gat@csn.org)]

6. Why won't my setup program install commdlg.dll et. al.?

   There are a couple of DLLs that are almost always in use by windows.
   Commdlg.dll is the most common example.  When faced with this problem,
   there is no easy way out.  The full explanation is several pages long
   and beyond the scope of this FAQ.  The general idea is as follows:

   Your setup program will need to create a .BAT file to expand and then
   copy these files.  Then, it will need to shutdown Windows  (see
   ExitWindowsExec API call) and run the .BAT file.  Then it will need to
   restart windows and continue your setup program.  Your setup program
   should delete the temporary .BAT file that is no longer needed.
   [George Tatge (gat@csn.org)]

7. Where do I install VBXs and DLLs?

   PLEASE- this is one place where everybody's life is much easier if you
   will follow Microsoft's recommendations.  All PUBLIC VBXs and DLLs
   should be installed in the windows/system directory!  A "PUBLIC" DLL or
   VBX is any which can be purchased on the open market.  In other words,
   if another VB programmer might possibly use the same VBX or DLL, install
   it in the system directory.

   If you have written private VBXs or DLLs that will never be used by any
   program but yours, you can install them in the same directory where you
   install your application files.

   There are lots of good reasons for doing this, but it makes a short
   novel to rehearse them all.
   [George Tatge (gat@csn.org)]


H. MISCELLANEOUS TIPS AND INFORMATION


1. Multiple identifiers after the DIM statement can be confusing

   Some programmers with background from Pascal can try the following

     Dim iA, iB, iC as Integer

   and think that all these 3 variables end up as Integer. In fact, the
   first two end up as default data type, normally Variant.

   Instead you should do

     Dim iA as Integer
     Dim iB as Integer
     Dim iC as Integer

   which takes up more space, but gives you room to comment your variables
   (hint, hint); *or*

     Dim iA%, iB%, iC%

   which does the whole job.

2. "Clean up" your project before final EXE compilation.

   When you are ready to compile your VB project into your 'finished' EXE,
   be sure to save the project files, exit VB, restart Windows, run VB,
   load your project and go straight to compiling. Otherwise, your EXE may
   be larger in file size than necessary due to 'garbage' getting included
   in the EXE. For some reason, VB does not fully clean up all of the
   previously used variables or objects that you may have been playing with
   while developing your program so these get included in your EXE even
   though they aren't used. Other VB users have even advocated saving all
   the project files as ASCII, then loading the ASCII files before
   compiling to further "clean up" the resulting EXE file.

3. Multiple END statements can be dangerous; or, The program that refused
   to terminate.

   Suggestion: put the END statement used to exit your program *only* in
   the Form_Unload event of the main form. Whenever you want to end the
   program, just tell the main form to unload.

   Some have reported that after their program have (supposedly)
   terminated, it still appears in the task list. This can happen if you
   only hide secondary forms and forget to unload them when you end/unload
   the main form.

   Also note that the Stop-button on the button-bar of the integrated
   development environment doesn't really unload anything. It *nukes* the
   program, which generally is a good idea since it could be a bug in it
   that caused it to be stuck in an eternal loop or something.

4. What are the latest versions of the various files used by VB?


   Date       File to download  Updates files    Description

   3/7/94     BTR110.EXE        BTRV110.DLL      Btrieve IISAM Driver

   3/7/94     DATAINDX.EXE      DATAINDX.DOC     "Data Access Guide"
                                                 Index

   3/7/94     GENERIC.EXE       \VB\CDK\GENERIC  Sample custom control
                                                 source

   3/7/94     VBGRID.EXE        GRID.VBX         Grid control

   3/7/94     VBHC505.EXE       HC.EXE, HCP.EXE  WinHelp compiler

   3/7/94     MSAJT.EXE         MSAJT110.DLL     Access Database Engine

   3/8/94     MSCOMM.EXE        MSCOMM.VBX       Serial


                                                 Communications\control

   3/7/94     ORA110.EXE        ORACLE.TXT       Updated ORACLE.TXT file

   6/27/94    SETUPK.EXE        SETUP.EXE        Setup Toolkit

   3/7/94     VBRUN300.EXE      VBRUN300.DLL     Visual Basic Runtime
                                                 Library

   3/7/94     XBS110.EXE        XBS110.DLL       XBase IISAM Driver


   There is an article in the Microsoft Knowledge Base that points to each
   of these files and provides more detailed information about the update.
   To find these articles, query the Microsoft Knowledge Base using the
   file name and the word "update3.00".

   Note the NEW SETUPKIT update!
   [Thanks to Marks Harrop <harrop@werple.apana.org.au>]

   Please inform the FAQ maintainer about newer versions.


I. VISUAL BASIC FOR APPLICATIONS (VBA)

1. Any tips for VB/Win 3 programmers moving to VBA?

   You are in for some surprises. VBA is more unlike VB 3 than most people
   thought. Especially the development environment is very different, and
   the language puts more emphasis on objects. The latter is a trend you
   can get used to for VB also.

   For Excel 5 VBA, be aware that the environment is based on the
   "workbook" idea Microsoft stole from Borland. Your controls will be
   placed in one sheet, and the code will be in another. Doubleclicking on
   the control to open the code window doesn't help. You have to use the
   "Tools|Assign Macro" menu option.

   Also, be aware that the list of events is nowhere close to what VB3
   supports! No GotFocus, no MouseMove, no nothing. You'll be very confused
   if you try to look for "events" in the VBA docs!

2. Does VBA support VBXs?

   No. If Microsoft have its way, VBX is a dead end. There will never be
   32-bit VBXs, but OCXs using OLE 2. VBA is more a subset of VB 4 than VB
   3, but it does not fully support OCX yet. It will, though.

3. How do I access properties on my dialog boxes in VBA?

   As noted above, VBA is a culture chock to VB programmers. If you create
   a textbox in VBA, call it txName and try to

     cMyVar=txName.Text

   the impolite interpreter will give you a "variable not defined" error.

   The magic is objects. You have to

     Dim txName as Object
     Set txName = DialogSheets("NameDialog".EditBoxes("txName"))

   And then you can access your properties like you used to in good ol' VB
   3. (Anyone volunteer to beat senseless the guy who thought out this?)

4. How do I use database routines from Excel VBA?

   The documentation is somewhere between sparse and inexistant on this
   topic. Any info on VBA and SQL would be much appreciated.

   Here Microsoft breaks the tradition and you *can't* use database
   objects, at least not the way you do in VB. Also, forget dynasets.

   I know nothing about databases in VBA. I just bring on the following
   tips from various magazines:

   Both SQLOpen and QueryGetData require a 'connection string'. That's
   about what the doc's say about the parameter. What is it? The doc is
   also tragically void of useful examples. Someone dug up the following
   example:

     "DSN=My data file;DBQ=c:\access\data.mdb;FIL=RedISAM;"

   which is about as understandable as it looks. If you use an empty
   string, you get a dialog which also can give you the string into a
   spreadsheet cell.

   Also, search for SQLREQUEST in the *main* help file for Excel 5 (not the
   VBA help!) for these examples of connection_string's:

   dBASE             DSN=NWind;PWD=test
   SQL Server        DSN=MyServer;UID=dbayer;PWE=123;Database=Pubs
   ORACLE            DNS=My Oracle Data Source;DBQ=MYSER VER;
                     |UID=JohnS;PWD=Sesame

   There's a KnowledgeBase on Excel 5 on ftp.microsoft.com. Last time I
   looked, it was void of database stuff. Still, it may be a good idea to
   download it as the situation may have changed now.


   *** END OF VB/WIN FAQ DOCUMENT ***


-- 
Kris Nosack      knosack@park.uvsc.edu

>>>--->  Be strange, but not a stranger!  <---<<<

