PRB: Binder95 Does Not Show an MFC DocObject Server Icon

• Microsoft Visual C++, 32-bit Edition, versions 4.2, 5.0

SYMPTOMS

Starting with Visual C++ 4.2, MFC provides support for creating Document Object (DocObject) Servers. The Binder application that comes with Microsoft Office '95 is a DocObject container. When you insert a DocObject server created by Visual C++ into the Binder, the defined icon for the document may not show up as expected.

CAUSE

The Binder application that comes with Microsoft Office '95 searches the registry for the CLSID of the DocObject server looking for the DefaultExtension key. It expects a certain format for this key to successfully display the correct icon. The MFC COleTemplateServer::UpdateRegistry() function does not register the information in this format.

RESOLUTION

The resolution involves changing the DefaultExtension key to the format that Binder expects after UpdateRegistry() is called. The sample code below demonstrates how this can be done. The code that accomplishes this is copied almost verbatim from the source code of COleTemplateServer::UpdateRegistry().

STATUS

This behavior is by design.

MORE INFORMATION

The following shows the difference between the DefaultExtension keys of an Office '95 application and an AppWizard generated application:

   Excel Worksheet:
      DefaultExtension = .xls, Excel Workbook (*.xls)

   AppWizard app named 'Test' with .tst extension:
      DefaultExtension = Test, Test Files (*.tst)

   DefaultExtension = .tst, Test Files (*.tst)

Sample Code

/* Compile options needed: None
*/

/* The following code can be added to the InitInstance of the CWinApp
   derived class right after the call to UpdateRegistry()
*/

   // change the DefaultExtension to work with Binder95.
   // Get registration info from document template string.
   CString strServerName;
   CString strLocalServerName;
   CString strLocalShortName;
   CString strLocalFilterName;
   CString strLocalFilterExt;

   if (!pDocTemplate->GetDocString(strServerName,
      CDocTemplate::regFileTypeId) || strServerName.IsEmpty())
      {
         TRACE0("Error: not enough information in DocTemplate to register"
                " OLE server.\n");
      }
   if (!pDocTemplate->GetDocString(strLocalServerName,
      CDocTemplate::regFileTypeName))
      strLocalServerName = strServerName;     // use non-localized name

   if (!pDocTemplate->GetDocString(strLocalShortName,
      CDocTemplate::fileNewName))
      strLocalShortName = strLocalServerName; // use long name

   pDocTemplate->GetDocString(strLocalFilterName,
      CDocTemplate::filterName);
   pDocTemplate->GetDocString(strLocalFilterExt, CDocTemplate::filterExt);

   ASSERT(strServerName.Find(' ') == -1);  // no spaces allowed

   // place entries in system registry
   LPCTSTR Arr[2];
   CString strDefExt("CLSID\\%1\\DefaultExtension");
   CString strEntry = strDefExt + (TCHAR)NULL + strLocalFilterExt + ","
      + strLocalFilterName;
   Arr[0] = strEntry;
   Arr[1] = NULL;
   if (!AfxOleRegisterServerClass(m_server.GetClassID(), strServerName,
      strLocalShortName, strLocalServerName, OAT_DOC_OBJECT_SERVER,
      NULL, Arr))
   {
      // not fatal (don't fail, just warn)
      AfxMessageBox(AFX_IDP_FAILED_TO_AUTO_REGISTER);
   }