This is an example of using the spreadsheet control with C only.  It
demonstrates how create a VBX control as the child of the main window.
Since the parent window of the control is resizeable, we respond to the
WM_SIZE event to resize the child window when its parent is resized.
Remeber to link bivbx.lib in with your project.

There are seven steps in this process.

1)  Initialize the Visual Basic emulator DLL.
This sets up BIVBX10.DLL for use with your application.  "Thunder" is a
class prefix used by Visual Basic.

2)  Create a form file.  At this point, the DLGINIT data is being used
to set up the form file.

3)  Create a control.  We use the form file as one of the parameters to
the create function.

4)  Respond to VBX Event.  All Visual Basic control generate the
WM_VBXFIREEVENT event.
In Visual Basic this event is automatically trapped and processed, but in C,
the application must trap this event.  lParam will contain a far pointer to
an event structure which can be used to determine which control caused the
event, and which event within the control is being triggered.

5)  Determine which VBX Event occurred.  The EventIndex member of the event
structure contains the index number of the event which occurred.  The
easiest way to get these indices is to look at the VBXGEN generated header
files.

6)  Decode the event arguments.  The macros VBX_EVENTARGNUM and
VBX_EVENTARGSTR are used to extract the event arguments.  The arguments
passed to each event are listed in the response functions in the VBXGEN
generated header files.

7)  Read a property of the control.  This involves three steps
  a) get the window handle of the control
  b) get the HCTL of the control
  c) use the HCTL and the appropriate API call to retrieve the data

In this case, we are calling GetDlgItem to get the window handle of the
control.  You may notice that the control contains an hWnd property, but
we can't use it yet because we need an HCTL before we can get ANY
properties of the control.

We are using VBXGetPropByName to access a property.  We could use VBXGetProp,
which retrieves a property by its index value.  The index values are
enumerated in the VBXGEN generated header files, and can also be retrieved
with the function VBXGetPropIndex.
