MFC中的指针

下表总结了MFC中获取各个类指针的方法，很全面，很简洁，很有参考价值。

From this class:	You can access this class using:
	CWinApp	CMainFrame	CChildFrame	CDocument	CView
CWinApp		AfxGetMainWnd() or m_pMainWnd	AfxGetMainWnd()-> MDIGetActive()	AfxGetMainWnd()-> GetActiveView()-> GetDocument()	AfxGetMainWnd()-> GetActiveView()
CMainFrame	AfxGetApp() or theApp		MDIGetActive() or GetActiveFrame()	SDI: GetActiveView()-> GetDocument() MDI: MDIGetActive()-> GetActiveView()-> GetDocument()	SDI: GetActiveView() MDI: MDIGetActive()-> GetActiveView()
CChildFrame	AfxGetApp() or theApp	GetParentFrame()		GetActiveView()-> GetDocument()	GetActiveView()
CDocument	AfxGetApp() or theApp	AfxGetMainWnd()	AfxGetMainWnd()-> MDIGetActive()		POSITION pos = GetFirstViewPosition(); GetNextView(pos); (see note below)
CView	AfxGetApp() or theApp	AfxGetMainWnd()	GetParentFrame()	GetDocument()
any other class	AfxGetApp()	AfxGetMainWnd()	AfxGetMainWnd()-> MDIGetActive() or AfxGetMainWnd()-> GetActiveFrame()	SDI:AfxGetMainWnd()-> GetActiveView()-> GetDocument() MDI:AfxGetMainWnd()-> MDIGetActive()-> GetActiveView()-> GetDocument()	SDI:AfxGetMainWnd()-> GetActiveView() MDI:AfxGetMainWnd()-> MDIGetActive()-> GetActiveView()
	Note: To access only the current view, the document class can call AfxGetMainWnd()->GetActiveView() from a SDI application or AfxGetMainWnd()->MDIGetActive()->GetActiveView() from a MDI application.