Article: Q193102
Product(s): Microsoft C Compiler
Version(s): winnt:6.0
Operating System(s):
Keyword(s): kbDocView kbMFC kbVC kbVC600 kbVS600sp2 kbVS600sp2bug kbVS600sp2fix kbVS600SP1fix kbMFC
Last Modified: 03-MAY-2001
-------------------------------------------------------------------------------
The information in this article applies to:
- The Microsoft Foundation Classes (MFC), used with:
- Microsoft Visual C++, 32-bit Enterprise Edition, version 6.0
- Microsoft Visual C++, 32-bit Professional Edition, version 6.0
- Microsoft Visual C++, 32-bit Learning Edition, version 6.0
-------------------------------------------------------------------------------
SYMPTOMS
========
When you try to display a modal window without explicitly specifying a parent in
a command handler of an MFC SDI/MDI application, where the frame window is
destroyed in the command handler before displaying the modal window, you might
get an assertion in CCmdTarget::GetRoutingFrame_() (Appui1.cpp line: 215) with
debug builds.
In the release builds of the application, modal windows may behave similar to
modeless windows. This will also be the case if you update an MFC application
from Visual C== 5.0 to Visual C++ 6.0 (both versions of Visual C++ use the MFC
DLL named MFC42.dll).
CAUSE
=====
Modal windows now use the routing frame data member (m_pRoutingFrame) of the
thread state to decide on the owner in GetSafeOwner(). The problem is that the
CFrameWnd set as the thread state's current routing frame is deleted, but the
thread state is not updated to reflect that fact.
RESOLUTION
==========
Set the thread state's current routing frame to NULL in the destructor of your
CFrameWnd derived class that is being destroyed:
CMyFrameWnd::~CMyFrameWnd()
{
if( AfxGetThreadState()->m_pRoutingFrame == this )
{
AfxGetThreadState()->m_pRoutingFrame = NULL;
}
}
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 the Visual Studio 6.0
Service Pack 1.
To obtain this service pack, please see:
http://msdn.microsoft.com/vstudio/sp/default.asp
For more information on the Visual Studio 6.0 Service Pack 1, please see the
following articles in the Microsoft Knowledge Base:
Q193009 INFO: Visual Studio 6.0 Service Pack 1 Readme
Q194022 INFO: Visual Studio 6.0 Service Packs, What, Where, Why
Q194295 HOWTO: Tell That Visual Studio 6.0 Service Packs Are Installed
MORE INFORMATION
================
The MFC frame windows affected by this problem can be of type CFrameWnd,
CMDIFrameWnd, CMDIChildWnd, and COleIPFrameWnd.
The MFC modal windows affected are:
- Dialog
- CPropertySheet
- Ole Property Sheet [invoked through [ASCII 150]
OleObject::DoVerb(OLEIVERB_PROPERTIES)]
- COleBusyDialog
- Message Box [invoked through AfxMessageBox()]
- MAPI modal window [when calling MAPISendMail()]
- SQL Driver Connection dialog box [when calling SQLDriverConnect()]
Steps to Reproduce Behavior
---------------------------
1. Use AppWizard to generate an MFC exe that is an MDI-based application.
2. Use ClassWizard to override OnCloseDocument of the CDocument class generated
by AppWizard.
3. Edit the OnCloseDocument member function as shown here:
void CMyDoc::OnCloseDocument()
{
CDocument::OnCloseDocument();
AfxMessageBox("The Document is Closed");
}
4. Build and run the application.
5. On the File menu, click Close.
RESULTS: The following error appears:
"Debug Assertion Failed! File: Appui1.cpp line: 215".
To correct this problem in the case mentioned above, add the following code in
the destructor for CChildFrame:
CChildFrame::~CChildFrame()
{
if( AfxGetThreadState()->m_pRoutingFrame == this )
{
AfxGetThreadState()->m_pRoutingFrame = NULL;
}
}
(c) Microsoft Corporation 1998, All Rights Reserved. Contributions by Bret
Bentzinger, Microsoft
Additional query words: connect MfcDocView
======================================================================
Keywords : kbDocView kbMFC kbVC kbVC600 kbVS600sp2 kbVS600sp2bug kbVS600sp2fix kbVS600SP1fix kbMFC600bug kbVC600SP1Fix
Technology : kbAudDeveloper kbMFC
Version : winnt:6.0
Issue type : kbbug
Solution Type : kbfix
=============================================================================