FIX: ASSERT in OLECLI1.CPP When Copying Embedding to Clipboard

WINDOWS        | WINDOWS NT

The information in this article applies to:

• The Microsoft Foundation Classes (MFC), included with: - Microsoft Visual C++ for Windows, versions 1.5, 1.51, 1.52 - Microsoft Visual C++, 32-bit Edition, versions 2.0, 2.1, 2.2, 4.0, 4.1

SYMPTOMS

When you attempt to copy an embedding in an in-place active object to the clipboard, the result is an ASSERT in OLECLI1.CPP. Specifically, the ASSERT occurs in the COleClientItem::XOleClientSite::GetMoniker() function on the following line of code:

   VERIFY(pThis->m_lpObject->SetMoniker(OLEWHICHMK_OBJREL,
          *ppMoniker)==S_OK);

CAUSE

When you copy an embedding to the clipboard, a number of data formats are placed on the clipboard, including link source information. The link source information contains a moniker used to locate the document in which the embedding resides.

When the container assigns a moniker to an embedded object, it will call the object's IOleObject::SetMoniker() function. The object will then call the container's IOleClientSite::GetMoniker() function to construct a composite moniker based on the container's moniker. This is done because the container may have changed its moniker while the object was not running.

When the embedded object calls IOleClientSite::GetMoniker() to get the container's moniker, COleClientItem::XOleClientSite::GetMoniker() ASSERTs on the aforementioned line of code because pThis->m_bMoniker had not been set to TRUE when the moniker was assigned during a previous call to COleClientItem::XOleClientSite::GetMoniker().

The problem is located in the following section of the COleClientItem::XOleClientSite::GetMoniker() function located in OLECLI1.CPP:

   // notify the object of the assignment
   if (dwAssign != OLEGETMONIKER_TEMPFORUSER &&
       *ppMoniker != NULL && !pThis->m_bMoniker)
   {
      VERIFY(pThis->m_lpObject->SetMoniker(
             OLEWHICHMK_OBJREL, *ppMoniker) == S_OK);
      pThis->m_bMoniker = TRUE;
      ASSERT_VALID(pThis->m_pDocument);
      pThis->m_pDocument->SetModifiedFlag();
   }

RESOLUTION

To work around this problem, you must override the default IOleClientSite interface implementation in COleClientItem. This can be done by adding an interface map to the class in your project that is derived from COleClientItem and setting pThis->m_bMoniker to TRUE before calling pThis- >m_lpObject->SetMoniker() from your custom GetMoniker() function.

The code below illustrates how to override the COleClientItem-derived object using the OCLIENT MFC sample application.

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. This bug was corrected in Visual C++ 32- bit Edtion version 4.2.

MORE INFORMATION

Sample Code

   // Code to be added to CRectItem class definition in RECTITEM.H
   class CRectItem : public COleClientItem
   {
      // ...original declarations in CRectItem class go here...

      // Interface Map
      BEGIN_INTERFACE_PART(OleClientSite2, IOleClientSite)
         STDMETHOD(SaveObject)();
         STDMETHOD(GetMoniker)(DWORD, DWORD, LPMONIKER*);
         STDMETHOD(GetContainer)(LPOLECONTAINER*);
         STDMETHOD(ShowObject)();
         STDMETHOD(OnShowWindow)(BOOL);
         STDMETHOD(RequestNewObjectLayout)();
      END_INTERFACE_PART(OleClientSite2)

      DECLARE_INTERFACE_MAP()
   };

   // XOleClientSite2 functions to be added to RECTITEM.CPP
   BEGIN_INTERFACE_MAP(CRectItem, COleClientItem)
      INTERFACE_PART(CRectItem, IID_IOleClientSite, OleClientSite2)
   END_INTERFACE_MAP()

   STDMETHODIMP_(ULONG) CRectItem::XOleClientSite2::AddRef()
   {
      METHOD_PROLOGUE_EX_(CRectItem, OleClientSite2)
      return pThis->ExternalAddRef();
   }

   STDMETHODIMP_(ULONG) CRectItem::XOleClientSite2::Release()
   {
      METHOD_PROLOGUE_EX_(CRectItem, OleClientSite2)
      return pThis->ExternalRelease();
   }

   STDMETHODIMP CRectItem::XOleClientSite2::QueryInterface(
      REFIID iid, LPVOID* ppvObj)
   {
      METHOD_PROLOGUE_EX_(CRectItem, OleClientSite2)
      return pThis->ExternalQueryInterface(&iid, ppvObj);
   }

   STDMETHODIMP CRectItem::XOleClientSite2::SaveObject()
   {
      METHOD_PROLOGUE_EX(CRectItem, OleClientSite2)
      ASSERT_VALID(pThis);
      return pThis->m_xOleClientSite.SaveObject();
   }

   STDMETHODIMP CRectItem::XOleClientSite2::GetMoniker(
       DWORD dwAssign, DWORD dwWhichMoniker, LPMONIKER* ppMoniker)
   {
      METHOD_PROLOGUE_EX(CRectItem, OleClientSite2)
      ASSERT_VALID(pThis);

      USES_CONVERSION;  // note, must #include afxpriv.h

      COleDocument* pDoc = pThis->GetDocument();
      ASSERT_VALID(pDoc);
      ASSERT(ppMoniker != NULL);
      *ppMoniker = NULL;

      switch (dwWhichMoniker)
      {
      case OLEWHICHMK_CONTAINER:
         // return the current moniker for the document
         *ppMoniker = pDoc->GetMoniker((OLEGETMONIKER)dwAssign);
         break;

      case OLEWHICHMK_OBJREL:
         {
            if (!pDoc->IsKindOf(RUNTIME_CLASS(COleLinkingDoc)))
            break;

            // don't return relative moniker if no document moniker
            LPMONIKER lpMoniker = pDoc-
   >GetMoniker((OLEGETMONIKER)dwAssign);
            if (lpMoniker == NULL)
               break;
            lpMoniker->Release();

            // relative monikers have to handle assignment correctly
            switch (dwAssign)
            {
               case OLEGETMONIKER_ONLYIFTHERE:
                  if (!pThis->m_bMoniker)
                     break;  // no moniker assigned, don't return one
                   // fall through...

               case OLEGETMONIKER_TEMPFORUSER:
               case OLEGETMONIKER_FORCEASSIGN:
                  {
                     // create item moniker from item name
                     TCHAR szItemName[OLE_MAXITEMNAME];
                     pThis->GetItemName(szItemName);
                     CreateItemMoniker(OLESTDDELIMOLE, T2COLE(szItemName),
                        ppMoniker);

                     // notify the object of the assignment
                     if (dwAssign != OLEGETMONIKER_TEMPFORUSER &&
                         *ppMoniker != NULL && !pThis->m_bMoniker)
                     {
                        pThis->m_bMoniker = TRUE;
                        VERIFY(pThis->m_lpObject->SetMoniker(
                            OLEWHICHMK_OBJREL, *ppMoniker) == S_OK);
                        ASSERT_VALID(pThis->m_pDocument);
                        pThis->m_pDocument->SetModifiedFlag();
                     }
                  }
                  break;

               case OLEGETMONIKER_UNASSIGN:
                  pThis->m_bMoniker = FALSE;
                  break;
            }
         }
         break;

      case OLEWHICHMK_OBJFULL:
         {
            // get each sub-moniker: item & document
            LPMONIKER lpMoniker1, lpMoniker2;
            GetMoniker(dwAssign, OLEWHICHMK_CONTAINER, &lpMoniker1);
            GetMoniker(dwAssign, OLEWHICHMK_OBJREL, &lpMoniker2);

            // create composite moniker
            if (lpMoniker1 != NULL && lpMoniker2 != NULL)
                ::CreateGenericComposite(lpMoniker1, lpMoniker2,
   ppMoniker);

            // release sub-monikers
            RELEASE(lpMoniker1);
            RELEASE(lpMoniker2);
         }
         break;
      }
      return *ppMoniker != NULL ? S_OK : E_FAIL;
   }

   STDMETHODIMP CRectItem::XOleClientSite2::GetContainer(LPOLECONTAINER*
      ppContainer)
   {
   #ifdef _DEBUG
      METHOD_PROLOGUE_EX(CRectItem, OleClientSite2)
   #else
      METHOD_PROLOGUE_EX_(CRectItem, OleClientSite2)
   #endif
      ASSERT_VALID(pThis);
      return pThis->m_xOleClientSite.GetContainer(ppContainer);
   }

   STDMETHODIMP CRectItem::XOleClientSite2::ShowObject()
   {
      METHOD_PROLOGUE_EX(CRectItem, OleClientSite2)
      ASSERT_VALID(pThis);
      return pThis->m_xOleClientSite.ShowObject();
   }

   STDMETHODIMP CRectItem::XOleClientSite2::OnShowWindow(BOOL fShow)
   {
      METHOD_PROLOGUE_EX(CRectItem, OleClientSite2)
      ASSERT_VALID(pThis);
      return pThis->m_xOleClientSite.OnShowWindow(fShow);
   }

   STDMETHODIMP CRectItem::XOleClientSite2::RequestNewObjectLayout()
   {
      return E_NOTIMPL;
   }