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

 Last reviewed: February 17, 1998
Article ID: Q167697
The information in this article applies to:
  • The Microsoft Foundation Classes (MFC) included with: - Microsoft Visual C++, 32-bit Editions, versions 4.0, 4.0a, 4.1, 4.2, 

         4.2b, 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;
   }

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. We are researching this bug and will post new information here in the Microsoft Knowledge Base as it becomes available.

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. 
Keywords          : AXSDKControls MfcOLE vcbuglist400 vcbuglist500 kberrmsg kbbug
Technology        : kbMfc kbole
Version           : Winnet:3.0,3.01,3.02,4.0,4.0a,4.1,5.0
Platform          : NT WINDOWS
Issue type        : kbbug

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Last reviewed: February 17, 1998
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