Q177103: FIX: ALT+Key Combination in Property Page Causes Stack Overflow

Article: Q177103
Product(s): Microsoft C Compiler
Version(s): winnt:5.0
Operating System(s): 
Keyword(s): kbole kbActiveX kbCOMt kbDlg kbMFC kbVC500bug kbVC600fix kbGrpDSMFCATL
Last Modified: 17-JUL-2001

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The information in this article applies to:

- The Microsoft Foundation Classes (MFC), used with:
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 5.0 
   - Microsoft Visual C++, 32-bit Professional Edition, version 5.0 
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SYMPTOMS
========

If you press an ALT+key combination (generating a WM_SYSCOMMAND) with keyboard
focus on the property page for an MFC ActiveX control and the key does not
correspond to a mnemonic on the page, you will get a stack overflow.

CAUSE
=====

COlePropertyPage::WindowProc() traps the WM_SYSCOMMAND and calls
IPropertyPageSite::TranslateAccelerator(). This function in turns sends the
WM_SYSCOMMAND message back to the page. This results in a recursion until you
run out of stack space.

RESOLUTION
==========

Override COlePropertyPage::WindowProc() and return TRUE if the message is a
WM_SYSCOMMAND; for example:

     LRESULT CMyPropPage::WindowProc(UINT msg, WPARAM wParam, LPARAM lParam)
     {

        //Return without processing if WM_SYSCOMMAND.
        if (WM_SYSCOMMAND == msg)
           return TRUE;
        else
           return COlePropertyPage::WindowProc(msg, wParam, lParam);
     }

STATUS
======

Microsoft has confirmed this to be a problem in the Microsoft products that are
listed at the beginning of this article. This problem was corrected in Visual
C++ version 6.0 for Windows.

REFERENCES
==========

(c) Microsoft Corporation 1997, All Rights Reserved. Contributions by Samson
Tanrena, Microsoft Corporation.


Additional query words: mfcole Stock PropertyPage CLSID_CFontPropPage CLSID_CColorPropPage CLSID_CPicturePropPage

======================================================================
Keywords          : kbole kbActiveX kbCOMt kbDlg kbMFC kbVC500bug kbVC600fix kbGrpDSMFCATL 
Technology        : kbAudDeveloper kbMFC
Version           : winnt:5.0
Issue type        : kbbug
Solution Type     : kbfix

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