MFC 六大關鍵技術之仿真——全局變量的調用

//MFC.H

#include <iostream.h>

class CObject
{
public:
  CObject::CObject()  {
                         cout << "CObject Constructor /n";
                      }
  CObject::~CObject() {
                         cout << "CObject Destructor /n";
                      }
};

class CCmdTarget : public CObject
{
public:
  CCmdTarget::CCmdTarget()  {
                               cout << "CCmdTarget Constructor /n";
                            }
  CCmdTarget::~CCmdTarget() {
                               cout << "CCmdTarget Destructor /n";
                            }
};

class CWinThread : public CCmdTarget
{
public:
  CWinThread::CWinThread()  {
                               cout << "CWinThread Constructor /n";
                            }
  CWinThread::~CWinThread() {
                               cout << "CWinThread Destructor /n";
                            }
};

class CWinApp : public CWinThread
{
public:
  CWinApp* m_pCurrentWinApp;

public:
  CWinApp::CWinApp()  {
                         cout << "CWinApp Constructor /n";
                         m_pCurrentWinApp = this;
                      }
  CWinApp::~CWinApp() {
                         cout << "CWinApp Destructor /n";
                      }
};

 

class CDocument : public CCmdTarget
{
public:
  CDocument::CDocument()   {
                              cout << "CDocument Constructor /n";
                           }

  CDocument::~CDocument()  {
                              cout << "CDocument Destructor /n";
                           }
};

class CWnd : public CCmdTarget
{
public:
  CWnd::CWnd()   {
                    cout << "CWnd Constructor /n";
                 }
  CWnd::~CWnd()  {
                    cout << "CWnd Destructor /n";
                 }
};

class CFrameWnd : public CWnd
{
public:
  CFrameWnd::CFrameWnd()   {
                              cout << "CFrameWnd Constructor /n";
                           }
  CFrameWnd::~CFrameWnd()  {
                              cout << "CFrameWnd Destructor /n";
                           }
};

class CView : public CWnd
{
public:
  CView::CView()   {
                      cout << "CView Constructor /n";
                   }
  CView::~CView()  {
                      cout << "CView Destructor /n";
                   }
};

// global function

CWinApp* AfxGetApp(); 

//----------------------------------------------------------------------------------------------------------------------------------------

//MFC.CPP

#include "my.h"  // it should be mfc.h, but for CMyWinApp definition, so...

extern CMyWinApp theApp;

CWinApp* AfxGetApp()
{
  return theApp.m_pCurrentWinApp;
}

//-------------------------------------------------------------------------------------------------------------------------------------

//MY.H

#include <iostream.h>
#include "mfc.h"

class CMyWinApp : public CWinApp
{
public:
  CMyWinApp::CMyWinApp()   {
                              cout << "CMyWinApp Constructor /n";
                           }
  CMyWinApp::~CMyWinApp()  {
                              cout << "CMyWinApp Destructor /n";
                           }
};

class CMyFrameWnd : public CFrameWnd
{
public:
  CMyFrameWnd()   {
                     cout << "CMyFrameWnd Constructor /n";
                  }
  ~CMyFrameWnd()  {
                     cout << "CMyFrameWnd Destructor /n";
                  }
};

//-------------------------------------------------------------------------------------------------------------------------------------

//MY.CPP

#include "my.h"

CMyWinApp theApp;

//------------------------------------------------------------------
// main
//------------------------------------------------------------------
void main()
{

CWinApp* pApp = AfxGetApp();

}
//------------------------------------------------------------------