Q153570: How to Pass One OLE Control to Another

Article: Q153570
Product(s): Microsoft Visual Basic for Windows
Version(s): 4.00 | 4.00
Operating System(s): 
Keyword(s): 
Last Modified: 11-JAN-2001

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The information in this article applies to:

- Microsoft Visual Basic Standard Edition, 32-bit, for Windows, version 4.0 
- Microsoft Visual Basic Professional Edition, 16-bit, for Windows, version 4.0 
- Microsoft Visual Basic Professional Edition, 32-bit, for Windows, version 4.0 
- Microsoft Visual Basic Enterprise Edition, 16-bit, for Windows, version 4.0 
- Microsoft Visual Basic Enterprise Edition, 32-bit, for Windows, version 4.0 
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SUMMARY
=======

It is possible to pass an OLE Automation Object as a parameter to a method of a
custom OLE control (.OCX). To do this, declare the OCX method to take a
parameter of type IDispatch *. An OLE control is essentially an OLE Automation
Object, so you can then pass one OLE Control to another using this technique.

MORE INFORMATION
================

In Visual Basic 4.0, all OLE controls except the intrinsic controls (TextBox,
PictureBox, Label, and so on) implement an Object Property. Except for the OLE
container control, this Object property refers to the primary IDispatch
interface of that OLE control. So, if you pass the object property of any OLE
control except the OLE container control to a method of another custom OLE
control, a pointer to the primary IDispatch interface (LPDISPATCH) of the source
OLE control is what is passed, so you can then access the methods and properties
of the source OLE control through this LPDISPATCH inside your custom OLE control
method.

If you have a method declared in your custom OLE control source code:

     void CTestCtrl::PassObject(LPDISPATCH lpDisp)
     {
         // TODO: Add your dispatch handler code here
         ...
     }

You can call this from Visual Basic as follows:

  Test1.PassObject DbGrid1.Object    'Pass the DBGrid control's primary
                                     'dispatch interface to your custom
                                     'control, Test1

Additional query words: 4.00 vb4win vb4all vbctrl

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Keywords          :  
Technology        : kbVBSearch kbAudDeveloper kbVB400Search kbVB400 kbVB16bitSearch
Version           : 4.00 | 4.00

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