Q171516: FIX: ActiveX Document DLL Causes GPF When Unloading Modal Form

Article: Q171516
Product(s): Microsoft Visual Basic for Windows
Version(s): 5.0
Operating System(s): 
Keyword(s): kbVBp500 kbVS97sp2fix kbGrpDSVB kbvbp500sp2fix
Last Modified: 11-JAN-2001

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The information in this article applies to:

- Microsoft Visual Basic Control Creation Edition for Windows, version 5.0 
- Microsoft Visual Basic Learning Edition for Windows, version 5.0 
- Microsoft Visual Basic Professional Edition for Windows, version 5.0 
- Microsoft Visual Basic Enterprise Edition for Windows, version 5.0 
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SYMPTOMS
========

A General Protection Fault (GPF) occurs in Internet Explorer when using ActiveX
UserDocument DLL.

CAUSE
=====

This behavior occurs when you attempt to unload a form within the Paint Event.

RESOLUTION
==========

This problem has been fixed in SP2. Visual Basic now catches the error and posts
an error message stating that the form can not be unloaded in this context.

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. This bug has been fixed in Visual Studio 97 Service
Pack 2.

For more information on the Visual Studio 97 Service Pack 2, please see the
following article in the Microsoft Knowledge Base:

  Q170365 : INFO: Visual Studio 97 Service Packs - What, Where, and Why

For a list of the Visual Basic 5.0 bugs that were fixed in the Visual Studio 97
Service Pack 2, please see the following article in the Microsoft Knowledge
Base:

  Q171554 : INFO: Visual Basic 5.0 Fixes in Visual Studio 97 Service Pack 2

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

Steps to Reproduce Behavior
---------------------------

1. Start a new ActiveX Document DLL project. UserDocument1 is created by
  default.

2. Add a CommandButton (Command1) to UserDocument1.

3. Add the following code to the Click event of Command1:

        Private Sub Command1_Click()
           Dim x As New Form1
           x.Show vbModal
        End Sub

4. Add a Form (Form1) to the project.

5. Add the following code to the Paint event of Form1:

        Private Sub Form_Paint()
           Unload Me
        End Sub

6. Press the F5 key to run the project.

7. Load the UserDocument1.vbd from the Visual Basic installation directory into
  Internet Explorer.

8. Click on Command1 button.

Additional query words: kbDSupport

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Keywords          : kbVBp500 kbVS97sp2fix kbGrpDSVB kbvbp500sp2fix 
Technology        : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB500Search kbVBA500Search kbVBA500 kbVB500 kbZNotKeyword3
Version           : 5.0
Issue type        : kbbug
Solution Type     : kbfix

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