Q113257: HOWTO: Create New Documents Without CWinApp::OnFileNew

Article: Q113257
Product(s): Microsoft C Compiler
Version(s): winnt:1.0,2.0,2.1,4.0,4.1,4.2,5.0,6.0
Operating System(s): 
Keyword(s): kbDocView kbMFC kbVC kbGrpDSMFCATL
Last Modified: 07-MAY-2001

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The information in this article applies to:

- The Microsoft Foundation Classes (MFC), used with:
   - Microsoft Visual C++ for Windows, 16-bit edition, versions 1.0, 1.5, 1.51, 1.52 
   - Microsoft Visual C++, 32-bit Editions, versions 1.0, 2.0, 2.1, 4.0, 4.1 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 4.2 
   - Microsoft Visual C++, 32-bit Professional Edition, version 4.2 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 5.0 
   - Microsoft Visual C++, 32-bit Professional Edition, version 5.0 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 6.0 
   - Microsoft Visual C++, 32-bit Professional Edition, version 6.0 
   - Microsoft Visual C++, 32-bit Learning Edition, version 6.0 
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SUMMARY
=======

It is sometimes desirable to create a CMultiDocTemplate based window (in other
words, a CFrame/CDocument/CView combination) without using the mechanism
provided by CWinApp::OnFileNew.

For example, if the program has multiple document templates, CWinApp::OnFileNew
will prompt the user with a dialog box asking which type of document to open.
The programmer may already know which type of CMultiDocTemplate to use, and
therefore may not want to prompt the user because it would be inappropriate in
the given context of the application.

MORE INFORMATION
================

Assuming the application was originally created with AppWizard, the undocumented
CMultiDocTemplate::OpenDocumentFile function can be used to create a new
CMultiDocTemplate based window. There are several steps involved:

1. Add a CMultiDocTemplate pointer to your CWinApp derived class:

        class CMyApp : public CWinApp
        {
          ...

         public:
          CMultiDocTemplate* m_pDocTemplate;

          ...

        }

  NOTE: If you plan to use multiple document types, you must create a
  CMultiDocTemplate pointer member variable for each document type.

2. In the call to CWinApp::InitInstance, remove the creation of the
  CMultiDocTemplate from the call to AddDocTemplate. Set the pointer to point
  to the new CMultiDocTemplate. Use the pointer to call AddDocTemplate:

        BOOL CMyApp::InitInstance()
        {
          ...

          m_pDocTemplate = new CMultiDocTemplate(IDR_TEXTTYPE,
                                        RUNTIME_CLASS(CMyDoc),
                                        RUNTIME_CLASS(CMDIChildWnd),
                                        RUNTIME_CLASS(CMyView));

          AddDocTemplate(m_pDocTemplate);

          ...

        }

3. Use the pointer to call CMultiDocTemplate::OpenDocumentFile with a NULL
  parameter to create the new window. For this example, assume there is a
  button in a CView window. In the BN_CLICKED handler for the button, we want
  to create a window based on m_pDocTemplate:

        void CMyView::OnNewWindowButtonClicked()
        {
            CMyApp* pApp = (CMyApp*)AfxGetApp();
            pApp->m_pDocTemplate->OpenDocumentFile(NULL);
        }

  This same technique could be used to create a CSingleDocTemplate based window
  in a Single Document Interface (SDI) application. However, it is not
  necessary. Because there is only one document template for the application,
  calling OnFileNew() will create the new window without prompting the user for
  the type of document.

Additional query words:

======================================================================
Keywords          : kbDocView kbMFC kbVC kbGrpDSMFCATL 
Technology        : kbAudDeveloper kbMFC
Version           : winnt:1.0,2.0,2.1,4.0,4.1,4.2,5.0,6.0
Issue type        : kbhowto

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