KnowledgeBase Archive

An Archive of Early Microsoft KnowledgeBase Articles

View on GitHub

Q257421: FIX: Compiling ActiveX Project Does Not Release Reference Right

Article: Q257421
Product(s): Microsoft Visual Basic for Windows
Version(s): WINDOWS:6.0
Operating System(s): 
Keyword(s): kbActiveX kbCOMt kbCtrl kbCtrlCreate kbVBp kbVBp600bug kbGrpDSVB kbDSupport kbVS600sp4f
Last Modified: 26-JUL-2001

-------------------------------------------------------------------------------
The information in this article applies to:

- Microsoft Visual Basic Professional Edition for Windows, version 6.0 
- Microsoft Visual Basic Enterprise Edition for Windows, version 6.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

After compiling a Visual Basic 6.0 ActiveX Control that uses an MFC ActiveX
Control, you receive the following error message when you exit Visual Basic:

  Debug Assertion Failed!

  Program: C:\PROGRAM FILES\MICROSOFT VISUAL STUDIO\VB98\VB6.EXE
  File: cmdtarg.cpp
  Line: 52

  For information on how your program can cause an assertion
  failure, see the Visual C++ documentation on asserts.

  (Press Retry to debug the application)

CAUSE
=====

The problem occurs when the reference to IClassFactory2 is not released by
Visual Basic.

STATUS
======

Microsoft has confirmed that this is a bug in the Microsoft products that are
listed at the beginning of this article. This bug was corrected in the latest
service pack for Visual Studio 6.0.

For additional information about Visual Studio service packs, click the following
article numbers to view the articles in the Microsoft Knowledge Base:

  Q194022 INFO: Visual Studio 6.0 Service Packs, What, Where, Why

  Q194295 HOWTO: Tell That a Visual Studio Service Pack Is Installed

To download the latest Visual Studio service pack, visit the following Microsoft
Web site:

  http://msdn.microsoft.com/vstudio/downloads/updates.asp

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

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

Create an MFC Control:

1. Start Microsoft Visual C++.

2. On the File menu, select New.

3. Select the Project tab and choose MFC ActiveX ControlWizard.

4. Enter the project name and click OK.

5. Use all of the project defaults.

6. Select Build <project name>.ocx from the Build menu or press the F7
  key.

Use an MFC Control in a Visual Basic ActiveX Control Project:

1. Start a new ActiveX Control project in Visual Basic. UserControl1 is created
  by default.

2. On the Project menu, select Components, or right-click on the Toolbox and
  select Components.

3. On the Components dialog box, check the MFC control that you just created,
  and then click OK.

4. Add the MFC control to the UserControl.

5. On the File menu, select Make Project1.ocx.

6. After compiling the project, close Visual Basic and note that the error
  occurs.

Additional query words: sp4

======================================================================
Keywords          : kbActiveX kbCOMt kbCtrl kbCtrlCreate kbVBp kbVBp600bug kbGrpDSVB kbDSupport kbVS600sp4fix kbVS600sp5fix 
Technology        : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB600Search kbVB600
Version           : WINDOWS:6.0
Issue type        : kbbug
Solution Type     : kbfix

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.