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Q167697: FIX: ActiveX Control in IE Asserts in CTLINPLC.CPP, Line 328

Article: Q167697
Product(s): Microsoft C Compiler
Version(s): winnt:4.0,4.0a,4.1,4.2,4.2b,5.0
Operating System(s): 
Keyword(s): kberrmsg kbole kbActiveX kbCOMt kbCtrl kbCtrlCreate kbIE300 kbIE301 kbMFC kbVC400bug kb
Last Modified: 17-JUL-2001

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

- The Microsoft Foundation Classes (MFC), used with:
   - Microsoft Visual C++, 32-bit Editions, versions 4.0, 4.0a, 4.1, 4.2b 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 4.2 
   - Microsoft Visual C++, 32-bit Professional Edition, version 4.2 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 5.0 
   - Microsoft Visual C++, 32-bit Professional Edition, version 5.0 
   - Microsoft Internet Explorer (Programming) versions 3.0, 3.01, 3.02 
-------------------------------------------------------------------------------

SYMPTOMS
========

Clicking on an MFC ActiveX control that is hosted in a frame in Internet
Explorer may cause an assert in CTLINPLC.CPP, line 328.

CAUSE
=====

The assert is in COleControl::BuildSharedMenu(), where it checks:

     if (m_pUIActiveInfo != NULL)
     {
        ASSERT(m_pUIActiveInfo->m_hSharedMenu != NULL);
        return TRUE;
     }

m_pUIActiveInfo->m_hSharedMenu will always be NULL because you are not doing
menu merging. m_pUIActiveInfo is set to NULL when the control is UI
de-activated. In this case, the control is inplace activated when you first
click on it, so COleControl::OnActivateInPlace() is called. This, in turn, calls
BuildSharedMenu(). When BuildSharedMenu() returns, but before
OnActivateInPlace() is exited, Internet Explorer calls
DoVerb(OLEIVERB_UIACTIVATE) on the control. This causes OnActivateInPlace() to
be re-entered and BuildSharedMenu() to be called again. Because the control has
not been UI-de-activated, m_pUIActiveInfo is not NULL.

RESOLUTION
==========

You need to prevent OnActivateInPlace() from being re-entered by overriding
OnActivateInPlace() and setting a static boolean flag to determine if it has
been re-entered. If that is the case, then return the following: "

     HRESULT CTestCtrl::OnActivateInPlace(BOOL bUIActivate, LPMSG pMsg)
     {
        static BOOL bInsideFunc = FALSE;
        if (!bInsideFunc)
        {
           bInsideFunc = TRUE;
           HRESULT hr = COleControl::OnActivateInPlace(bUIActivate, pMsg);
           bInsideFunc = FALSE;
           return hr;
        }
        return S_OK;
     }

" (without the quotation marks)

STATUS
======

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

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

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

1. Put an MFC ActiveX control in a frame in Internet Explorer.

2. Click on the control.

3. Click on a different frame.

4. Click back on the control.

Additional query words:

======================================================================
Keywords          : kberrmsg kbole kbActiveX kbCOMt kbCtrl kbCtrlCreate kbIE300 kbIE301 kbMFC kbVC400bug kbVC410bug kbVC420bug kbVC500bug kbVC600fix kbIE302 kbGrpDSMFCATL kbNoUpdate 
Technology        : kbAudDeveloper kbMFC
Version           : winnt:4.0,4.0a,4.1,4.2,4.2b,5.0
Issue type        : kbbug
Solution Type     : kbfix

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

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