DOCUMENT:Q157893  04-AUG-2001  [visualc]
TITLE   :FIX: Closing an ActiveX Control Project Crashes DevStudio
PRODUCT :Microsoft C Compiler
PROD/VER:4.20
OPER/SYS:
KEYWORDS:kbole kbCtrl _IK920 kbVC kbVC420bug kbGrpDSToolskbbuglist kbfixlist

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

 - The Microsoft Foundation Classes (MFC), included with:
    - Microsoft Visual C++, 32-bit Enterprise Edition, version 4.2 
    - Microsoft Visual C++, 32-bit Professional Edition, version 4.2 
-------------------------------------------------------------------------------

SYMPTOMS
========

When opening or closing a project in Developer Studio, you may see an access
violation with the following error message:

   

   [ASCII 147]MSDEV CAUSED AN INVALID PAGE FAULT IN MODULE
     MSVCRES.DLL at   0137:503126ba.[ASCII 148]

This behavior occurs if the Properties window for a ControlWizard- generated
ActiveX Control is invoked in the dialog editor.

CAUSE
=====

This is due to a bug in the MFC 4.2 libraries.

RESOLUTION
==========

To obtain this patch, please refer to the following article in the Microsoft
Knowledge Base:

   Q156934 Visual C++ 4.2b Patch

The problem occurs because IOleObject::SetClientSite(NULL) does not release its
existing pointer to ambient property interface. For example,
COleControl::XOleObject::SetClientSite(NULL) doesn[ASCII 146]t call
pThis->m_ambientDispDriver.ReleaseDispatch();.

The problem was fixed by adding the following line to
COleControl::XOleObject::SetClientSite in the MFC source code:

      // Release existing pointer to ambient property dispinterface.
      pThis->m_ambientDispDriver.ReleaseDispatch();
      if (pClientSite != NULL)

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. This bug was corrected in Visual C++ 4.2B patch.

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

Steps to Reproduce Problem
--------------------------

1. Create a new ActiveX Control using Control Wizard, and then build the control
   to register it.

2. Create a new MFC Control Container application, and insert this OLE control
   into the About box.

3. Double-click on the control to bring up the Properties window. Click on any
   tab of the Properties window.

4. Close the project workspace, open a new project workspace, or close Developer
   Studio. Note that Developer Studio crashes with a page fault message.

If you have an existing project that has a Control Wizard-generated control built
with Visual C++ 4.2 in a dialog resource, click on the [ASCII 147]Control[ASCII
148] tab in the Properties window for the control, and then close the project,
open a new project, or close Developer Studio.

Additional query words: 4.20 vcfixlist420 kbdsi

======================================================================
Keywords          : kbole kbCtrl _IK920 kbVC kbVC420bug kbGrpDSTools kbbuglist kbfixlist
Technology        : kbAudDeveloper kbMFC
Version           : 4.20
Issue type        : kbbug
Solution Type     : kbfix

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

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