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CWinApp and CDocManager problem

I derived a CDocManager class named CMyDocManager. and I derived a CWinApp class named CMyWinApp. And I declared a member var in CMyWinApp as CMyDocManager m_pDocManager. But in my overloading virtual function OpenDocumentFile(), the m_pDocManager doesn't work properly. Here's the problem:
m_pDocManager is CMyDocManager var. I haven't initialize it. But the CWinApp::m_pDocManager is initialied. How can I initialize my own m_pDocManager? Or how can I change the functions of CDocManager m_pDocManager?
here's codes:
class CMyWinApp:public CWinApp
{
....
CMyDocManager m_pDocManager;
virtual void function();//overloaded
};
class CMyDocManager :public CDocManager
{
virtual void func(); //overloaded
};
void CMyWinApp::function()
{
m_pDocManager->func();
// a error occurs here( m_pDocManager == NULL)
}
Thanks in advanced.
0
speedup
Asked:
speedup
1 Solution
 
danny_pavCommented:
CDocManager is not a documented class.  Any answer given could be broken in later versions of MFC.  What exactly are you trying to do? Maybe documented features can be overrided which will be a more stable answer.

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speedupAuthor Commented:
hi,danny_pav
In fact, I want to change the behavier of OpenDocumentFile() when
the file I want to open is already opened instead of doing nothing.
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danny_pavCommented:
Why not derive a class from CDocTemplate?  This has the OpenDocumentFile() as a virtual.  Plus it's easy to plug this in to your app.  You can edit your code in InitInstance to create your document template instead of the one the AppWizard suggested.

Also what exactly are you trying to do?

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speedupAuthor Commented:
here's for danny_pav:
I open a file with extension .tpc, and when I open the same file again, there's nothing happened. because the file has been opened. I want to change the behavior when I open the same file that is already opened, it close the file and open it again. so I can get the new content that has been updated when it's opened.
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danny_pavCommented:
So you want to refresh the file.  Why not add a refresh toolbar button/menu item/accelerator and do the appropriate code in response. Do you need help coding that?
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speedupAuthor Commented:
But it is so horrible that I write a program for some dummies:-(, so i can't use toolbar. If I do that, my boss will told me that it's too difficult to use for our customers. So I want some automatic feathers.

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danny_pavCommented:
Assuming you can handle the refresh code, you can override
CWinApp::OpenDocumentFile().

class CMyWinApp : public CWinApp {

private:
BOOL m_bRefreshNow;

public:
BOOL MustRefreshDoc() const { return m_bRefershNow; }

public:
virtual CDocument* OpenDocumentFile(LPCTSTR lpsz) {
m_bRefreshNow = TRUE;
CDocument* pDoc = CWinApp::OpenDocumentFile(lpsz);
m_bRefreshNow = FALSE;
return pDoc;
}

};

Then in your mainframe's OnActivateFrame -- check the app's refersh flag and if TRUE-> refresh the document.  Of course, you should set the flag to False in the constructor.  This will work for SDI and MDI.





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speedupAuthor Commented:
I've found a way to solve the problem.
codes go here:
CDocument* CRefreshApp::OpenDocumentFile(LPCTSTR lpszFileName)
{
      CDocument* pOpenDocument = NULL;
      CDocTemplate::Confidence bestMatch = CDocTemplate::noAttempt;
      CDocTemplate *pDocTemplate;
      POSITION pos = GetFirstDocTemplatePosition();
      while( pos != NULL )
      {
            pDocTemplate = GetNextDocTemplate( pos );
            ASSERT_KINDOF(CDocTemplate, pDocTemplate);
            CDocTemplate::Confidence match;
            match = pDocTemplate->MatchDocType(lpszFileName, pOpenDocument);
            if (match > bestMatch)
            {
                  bestMatch = match;
            }
            if (match == CDocTemplate::yesAlreadyOpen)
            {
                  pOpenDocument->OnCloseDocument();
                  return OpenDocumentFile( lpszFileName );
            }
      }
      return CWinApp::OpenDocumentFile( lpszFileName );
}
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danny_pavCommented:
why was my answer rejected?
0
 
speedupAuthor Commented:
I've tried your answer, but seems to fail.
0
 
danny_pavCommented:
where/when did it fail?  I use this technique and have no problems
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TangChengCommented:
  You must create a CMyDocManager's class example, Then the App can automatism initial this class, then you can use this class.
   I often use this idea to write my DocManager class.

eg.
    class CMyWinApp:public CWinApp
    {
    ....
    CMyDocManager m_DocManager; //Declare a example,don't declare
                                //a point      
    virtual void function();//overloaded
    };

    class CMyDocManager :public CDocManager
    {
    virtual void func(); //overloaded
    };

    void CMyWinApp::function()
    {
    m_DocManager.func(); //then you can call this funciton ok.
    }
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speedupAuthor Commented:
TangCheng,
Your proposed answer can't work, coz m_pMyDocManager and the original m_pDocManager are different data member. m_pMyDocManager can't get initialized data automatically from m_pDocManager. Just try it and you will get the result.

Reguards,

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elf_kCommented:
Try to do something like that.
class CMyDocManager : public CDocManager
{
// override what you want here
};

class CMyApp : public CWinApp
{
 virtual BOOL InitApplication()
 {  // best time to init here
    CDocManager::pStaticDocManager=new CMyDocManager;
    // rest of init is doing by MFC
    CWinApp::InitApplication();
 }
};

That's all. You don't need to create a m_pDocManager variable in CMyApp, because it is already exist in CWinApp, and used by many of the functions and command handlers of CWinApp.
I have no time to test it, but it must work, according to MFC source code.

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