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Using ATL to Automate an MFC application

  • August 11, 2000
  • By Bart De Lathouwer
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Acknowledgements

This article is an extension of the article "Using ATL to Automate an MFC application" by Nick Hodapp.

Introduction

The AutoATL application works fine, but had a serious missing feature: new documents could not be created by client applications. Also the application is not visible. Mr Nick Hodapp is also working on this subject and might release it in the future. So keep watching this section.

  1. Lets start first to make the application visible. Add a property 'Visible' as a VARIANT_BOOL. The code should look like this:
    //-----------------------------------------------
    // get & put_Visible
    //-----------------------------------------------
    //
    STDMETHODIMP
    CAutoATLApp::get_Visible(VARIANT_BOOL *pVal)
    {
     METHOD_PROLOGUE_ATL
    
     CWnd* pMainWnd = AfxGetMainWnd();
     ASSERT(pMainWnd);
     *pVal = pMainWnd->IsWindowVisible();
    
     return S_OK;
    }
    
    STDMETHODIMP
    CAutoATLApp::put_Visible(VARIANT_BOOL newVal)
    {
     METHOD_PROLOGUE_ATL
    
     CWnd* pMainWnd = AfxGetMainWnd();
     ASSERT(pMainWnd);
     pMainWnd->ShowWindow(SW_SHOW);
     pMainWnd->UpdateWindow();
    
     return S_OK;
    }
  2. When i document i created by a client no frame or views are created. To be able to do so we must override CreateNewDocument in CMultiDocTemplate. CreateNewDocument is called from OpenDocumentFile to create a new document. But the document already exists. CrateNewDocument should therefor be altered NOT to create a document. Create a new class that inherites from CMultiDocTemplate and override CreateNewDocument and add a member variable CDocument* m_pDocument. CreateNewDocument should look like this:
    CDocument*
    CAnotherMultiDocTemplate::CreateNewDocument()
    {
     // default implementation constructs one from CRuntimeClass
     if (m_pDocClass == NULL)
     {
      TRACE0("Error: you must override "
             "CDocTemplate::CreateNewDocument.\n");
      ASSERT(FALSE);
      return NULL;
     }
    
    //-----------------------------------------------
    //    BdL; Document has already been created!
    //
    //    CDocument* pDocument = 
    //       (CDocument*)m_pDocClass->CreateObject();
    //-----------------------------------------------
     if (m_pDocument == NULL)
     {
      TRACE1("Warning: Dynamic create of document "
             "type %hs failed.\n",
      m_pDocClass->m_lpszClassName);
      return NULL;
     }
    
     ASSERT_KINDOF(CDocument, m_pDocument);
     AddDocument(m_pDocument);
     return m_pDocument;
    }

    To make your life a bit more easy, add the header file (AnotherMultiDocTemplate.h) of the new class to stdafx.h

  3. Alter in InitInstance of the application the DocumentTemplate:
    // CMultiDocTemplate* pDocTemplate;           
    // pDocTemplate = new CMultiDocTemplate(
    to
    CAnotherMultiDocTemplate* pDocTemplate;
    pDocTemplate = new CAnotherMultiDocTemplate(
  4. Add FinalConstruct and FinalRelease to CAutoATLDoc. FinalConstruct will continue to create Frame and View. FinalRelease will the necessary cleanup.

    Add the following lines to CAutoAtlDoc.h

    HRESULT FinalConstruct();
    void    FinalRelease();

    Add the following lines to CAutoAtlDoc.cpp

    HRESULT
    CAutoATLDoc::FinalConstruct()
    {
     METHOD_PROLOGUE_ATL
    
     CAutoATLApp* pApp = (CAutoATLApp*)AfxGetApp();
     ASSERT_VALID(pApp);
    
     // Find document template
     POSITION pos = pApp->GetFirstDocTemplatePosition();
     CAnotherMultiDocTemplate* pDocClass = 
      (CAnotherMultiDocTemplate*)pApp->GetNextDocTemplate(pos);
    
     ASSERT_VALID(pDocClass);
    
     // Create view and frame
     pDocClass->m_pDocument = this;
     pDocClass->OpenDocumentFile(NULL, true);
    
     return S_OK;
    }
    
    void
    CAutoATLDoc::FinalRelease()
    {
     // Do will still have a View connected?
     // (The frame will no longer exist if the document
     // has been closed manually, because the OnClose
     // message is passed BEFORE deleting the document)
     POSITION pos = GetFirstViewPosition();
     if (pos != NULL) {
      // Prevent the document from deleting itself already.
      m_bAutoDelete = false;
      OnCloseDocument();
      m_bAutoDelete = true;
     }
    }
  5. In the application override OnFileOpen, OnFileNew and OpenDocumentFile. Normally OnFileOpen and OnFileNew create a document AND the frame and view. Now the frame and view are now created in the FinalConstruct of CAutoAtlDoc.
    //-----------------------------------------------
    // 
    //-----------------------------------------------
    //
    void
    CAutoATLApp::OnFileNew() 
    {
     // Dynamically create a new CFuchiaDocument.
     // The document will continue to create itself
     // in the constructor.
     IMPLEMENT_CREATE_DOCUMENT;
    }
    
    void
    CAutoATLApp::OnFileOpen() 
    {
     // prompt the user (with all document templates)
     CString _lpszPathName;
     if (!DoPromptFileName(_lpszPathName, 
                           AFX_IDS_OPENFILE,
                           OFN_HIDEREADONLY | OFN_FILEMUSTEXIST,
                           TRUE, NULL))
      return; // open cancelled
    
     OpenDocumentFile(_lpszPathName);
    }
    
    CDocument*
    CAutoATLApp::OpenDocumentFile(LPCTSTR lpszFileName) 
    {
     // Dynamically create a new CFuchiaDocument.
     // The document will continue to create itself
     // in the constructor.
     IMPLEMENT_CREATE_DOCUMENT;
    
     // Open an existing document
     CWaitCursor wait;
     if ( !pDoc->OnOpenDocument( lpszFileName ) )
     {
      // Unable to open the document.
      TRACE( "Unable to open the document \
      in %s at %d.\n", THIS_FILE, __LINE__ );
      // We must delete the document instance.
      pDoc->Release();
      return NULL;
     }
    
     // Set the document file path and name.
     pDoc->SetPathName(lpszFileName);
     return pDoc;
    }
    
  6. IMPLEMENT_CREATE_DOCUMENT is a macro you can put on top in the document header file.
    //-----------------------------------------------
    // Call this MACRO when you need to create a new Document.
    // The document will construct itself further inside
    // FinalConstruct.
    #define IMPLEMENT_CREATE_DOCUMENT \
     CComObject<CAutoATLDoc>* pDoc; \
     HRESULT hr = CComObject<CAutoATLDoc>::CreateInstance(&pDoc); \
     ASSERT(SUCCEEDED(hr)); \
     pDoc->InternalAddRef();
    //-----------------------------------------------
    

Downloads

Download demo project - 44 Kb

History

Date Posted: August 11, 2000






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