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

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. This problem was corrected in Visual C++ version 6.0 for Windows.

MORE INFORMATION

Steps to Reproduce Behavior

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

Click on the control.

Click on a different frame.

Click back on the control.

Additional query words:

Keywords : kberrmsg kbole kbIE300 kbIE301 kbMFC kbVC400bug kbVC410bug kbVC420bug kbVC500bug kbVC600fix kbIE302 AXSDKControls
Version : Winnet:3.0,3.01,3.02,4.0,4.0a,4.1,5.0
Platform : NT WINDOWS
Issue type : kbbug