视图类CView

　　在MFC"文档/视图"架构中，CView类是所有视图类的基类，它提供了用户自定义视图类的公共接口。在"文档/视图"架构中，文档负责管理和维护数据；而视图类则负责如下工作：

　　（1） 从文档类中将文档中的数据取出后显示给用户；

　　（2） 接受用户对文档中数据的编辑和修改；

　　（3） 将修改的结果反馈给文档类，由文档类将修改后的内容保存到磁盘文件中。

　　文档负责了数据真正在永久介质中的存储和读取工作，视图呈现只是将文档中的数据以某种形式向用户呈现，因此一个文档可对应多个视图。

　　下面我们来看看CView类的声明：

class CView : public CWnd { 　DECLARE_DYNAMIC(CView) 　// Constructors protected: 　CView(); 　// Attributes public: 　CDocument* GetDocument() const; 　// Operations public: 　// for standard printing setup (override OnPreparePrinting) 　BOOL DoPreparePrinting(CPrintInfo* pInfo); 　// Overridables public: 　virtual BOOL IsSelected(const CObject* pDocItem) const; // support for OLE 　// OLE scrolling support (used for drag/drop as well) 　virtual BOOL OnScroll(UINT nScrollCode, UINT nPos, BOOL bDoScroll = TRUE); 　virtual BOOL OnScrollBy(CSize sizeScroll, BOOL bDoScroll = TRUE); 　// OLE drag/drop support 　virtual DROPEFFECT OnDragEnter(COleDataObject* pDataObject,DWORD dwKeyState, CPoint point); 　virtual DROPEFFECT OnDragOver(COleDataObject* pDataObject,DWORD dwKeyState, CPoint point); 　virtual void OnDragLeave(); 　virtual BOOL OnDrop(COleDataObject* pDataObject,DROPEFFECT dropEffect, CPoint point); 　virtual DROPEFFECT OnDropEx(COleDataObject* pDataObject, 　DROPEFFECT dropDefault, DROPEFFECT dropList, CPoint point); 　virtual DROPEFFECT OnDragScroll(DWORD dwKeyState, CPoint point); 　virtual void OnPrepareDC(CDC* pDC, CPrintInfo* pInfo = NULL); 　virtual void OnInitialUpdate(); // called first time after construct protected: 　// Activation 　virtual void OnActivateView(BOOL bActivate, CView* pActivateView,CView* pDeactiveView); 　virtual void OnActivateFrame(UINT nState, CFrameWnd* pFrameWnd); 　// General drawing/updating 　virtual void OnUpdate(CView* pSender, LPARAM lHint, CObject* pHint); 　virtual void OnDraw(CDC* pDC) = 0; 　// Printing support 　virtual BOOL OnPreparePrinting(CPrintInfo* pInfo); 　// must override to enable printing and print preview 　virtual void OnBeginPrinting(CDC* pDC, CPrintInfo* pInfo); 　virtual void OnPrint(CDC* pDC, CPrintInfo* pInfo); 　virtual void OnEndPrinting(CDC* pDC, CPrintInfo* pInfo); 　// Advanced: end print preview mode, move to point 　virtual void OnEndPrintPreview(CDC* pDC, CPrintInfo* pInfo, POINT point,CPreviewView* pView); 　// Implementation public: 　virtual ~CView(); 　#ifdef _DEBUG 　　virtual void Dump(CDumpContext&) const; 　　virtual void AssertValid() const; 　#endif //_DEBUG 　// Advanced: for implementing custom print preview 　BOOL DoPrintPreview(UINT nIDResource, CView* pPrintView,CRuntimeClass* pPreviewViewClass, CPrintPreviewState* pState); 　virtual void CalcWindowRect(LPRECT lpClientRect,UINT nAdjustType = adjustBorder); 　virtual CScrollBar* GetScrollBarCtrl(int nBar) const; 　static CSplitterWnd* PASCAL GetParentSplitter(const CWnd* pWnd, BOOL bAnyState); protected: 　CDocument* m_pDocument; public: 　virtual BOOL OnCmdMsg(UINT nID, int nCode, void* pExtra,AFX_CMDHANDLERINFO* pHandlerInfo); protected: 　virtual BOOL PreCreateWindow(CREATESTRUCT& cs); 　virtual void PostNcDestroy(); 　// friend classes that call protected CView overridables 　friend class CDocument; 　friend class CDocTemplate; 　friend class CPreviewView; 　friend class CFrameWnd; 　friend class CMDIFrameWnd; 　friend class CMDIChildWnd; 　friend class CSplitterWnd; 　friend class COleServerDoc; 　friend class CDocObjectServer; 　//{{AFX_MSG(CView) 　　afx_msg int OnCreate(LPCREATESTRUCT lpcs); 　　afx_msg void OnDestroy(); 　　afx_msg void OnPaint(); 　　afx_msg int OnMouseActivate(CWnd* pDesktopWnd, UINT nHitTest, UINT message); 　　// commands 　　afx_msg void OnUpdateSplitCmd(CCmdUI* pCmdUI); 　　afx_msg BOOL OnSplitCmd(UINT nID); 　　afx_msg void OnUpdateNextPaneMenu(CCmdUI* pCmdUI); 　　afx_msg BOOL OnNextPaneCmd(UINT nID); 　　// not mapped commands - must be mapped in derived class 　　afx_msg void OnFilePrint(); 　　afx_msg void OnFilePrintPreview(); 　/

上一篇：深入浅出MFC文档/视图架构之文档   下一篇：使用SDL打造游戏世界之入门篇