Q235414: PRB: ParentControls Property May Not Work with Some Containers

Article: Q235414
Product(s): Microsoft Visual Basic for Windows
Version(s): WINDOWS:5.0,6.0
Operating System(s): 
Keyword(s): kbCtrlCreate kbVBp500 kbVBp600 kbGrpDSO kbDSupport
Last Modified: 11-JAN-2001

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The information in this article applies to:

- Microsoft Visual Basic Professional Edition for Windows, versions 5.0, 6.0 
- Microsoft Visual Basic Enterprise Edition for Windows, versions 5.0, 6.0 
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SYMPTOMS
========

The ParentControls Collection of a Visual Basic UserControl is empty when the
control is placed in a non-Visual Basic Container.

CAUSE
=====

The ParentControls property is designed to return a Collection of all the
controls situated on a Form, UserDocument, or other UserControl. This property
is exposed by the Visual Basic extender object, and it is the responsibility of
the host container to implement the code needed to fill the collection. Not all
containers will support this feature. Consequently, this property might return
an empty collection in containers that do not support it.

STATUS
======

This behavior is by design.

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

Steps to Build Control
----------------------

1. Start Visual Basic and select New ActiveX Control. UserControl1 is created by
  default.

2. Change the name of the UserControl1 to MyControl and the Project name to
  MyControlServer.

3. Place a listbox and a CommandButton on the control, and in the click event of
  the CommandButton, put the following code:

      List1.Clear
      Dim x As Object
      For Each x In UserControl.ParentControls
          List1.AddItem x.Name
      Next

4. Save the project and compile to build an OCX.

Steps to Create a Visual Basic Container
----------------------------------------

1. Start Visual Basic and select New Standard EXE. Form1 is created by default.

2. Place a few controls on Form1. (The type of controls is not important.)

3. From the Project menu, select Components. From the Components list, select
  MyControlServer to add your custom control to the control toolbox.

4. Insert an instance of this control on Form1.

5. Run the project by pressing the F5 key. When you click on the CommandButton
  of MyControl1, the list box will be filled with all the names of the controls
  on Form1 (including your custom control).

Steps to Create a Visual Basic for Applications Container
---------------------------------------------------------

1. Start Microsoft Word and go to the Visual Basic Editor (ALT+F11).

2. Insert a UserForm in your project.

3. Place a few controls on the form. (The type of controls is not important.)

4. Click the right-mouse button on the Toolbox Controls and select Additional
  Controls.

5. Select MyControlServer.MyControl from the list.

6. Insert an instance of this control on the form.

7. Run the form and click on the CommandButton of your custom control. You will
  notice that the list box is not filled because the ParentControls Collection
  is empty. The Collection is empty because VBA does not implement this
  property.

(c) Microsoft Corporation 1999, All Rights Reserved.
Contributions by Harsha Bennur, Microsoft Corporation


Additional query words:

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Keywords          : kbCtrlCreate kbVBp500 kbVBp600 kbGrpDSO kbDSupport 
Technology        : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB500Search kbVB600Search kbVBA500 kbVBA600 kbVB500 kbVB600
Version           : WINDOWS:5.0,6.0
Issue type        : kbprb

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