MFC CCmdTarget Class成员变量及成员函数

一、概要说明

        该类派生于CObject，它封装了MFC的消息映射机制，希望接收系统事件和窗口消息的类都从它派生，如CDocument和CWnd分支。此外，在系统繁忙，无法响应窗口消息时，鼠标光标应该显示为沙漏形等待状态，CCmdTarget类封装了3个成员函数完成该功能。CCmdTarget类以一种类似消息映射的机制提供IDispatch接口，所以使用MFC可以轻松地编写AUTOMATION客户程序和组件。

二、类继承关系图

                     

三、CCmdTarget主要成员函数

   属性
      FromIDispatch返回一个指向CCmdTarget对象的指针，该对象与IDispatch相联系
      GetIDispatch返回一个指向IDispatch对象的指针，该对象与CCmdTarget对象相关
      IsResultExpected如果自动函数要返回一个值，则返回非零值
   操作
      BeginWaitCursor显示沙漏标
      EnableAutomation允许CCmdTarget对象的OLE自动函数
      EndWaitCursor返回到前一个光标
      RestoreWaitCursor重置沙漏标
   可覆盖的函数
      OnCmdMsg分派命令消息
      OnFinalRelease在最后一个OLE对象参考被释放时清除环境

四、CCmdTarget头文件

class AFX_NOVTABLE CCmdTarget : public CObject
{
	DECLARE_DYNAMIC(CCmdTarget)
protected:

public:
// Constructors
	CCmdTarget();
	///构造函数

// Attributes
	LPDISPATCH GetIDispatch(BOOL bAddRef);
		// retrieve IDispatch part of CCmdTarget
	static CCmdTarget* PASCAL FromIDispatch(LPDISPATCH lpDispatch);
		// map LPDISPATCH back to CCmdTarget* (inverse of GetIDispatch)
	BOOL IsResultExpected();
		// returns TRUE if automation function should return a value

// Operations
	void EnableAutomation();
		// call in constructor to wire up IDispatch
	void EnableConnections();
		// call in constructor to wire up IConnectionPointContainer

	void BeginWaitCursor();
	///显示沙漏光标
	
	/////※之间加入耗费机时的处理过程
	
	void EndWaitCursor();
	/////恢复为沙漏前的光标形状
	
	void RestoreWaitCursor();       // call after messagebox
	///重新将光标设置回沙漏形状，直到处理结束后调用EndWait Cursor()

#ifndef _AFX_NO_OLE_SUPPORT
	// dispatch OLE verbs through the message map
	BOOL EnumOleVerbs(LPENUMOLEVERB* ppenumOleVerb);
	BOOL DoOleVerb(LONG iVerb, LPMSG lpMsg, HWND hWndParent, LPCRECT lpRect);
#endif

// Overridables
	// route and dispatch standard command message types
	//   (more sophisticated than OnCommand)
	virtual BOOL OnCmdMsg(UINT nID, int nCode, void* pExtra,
		AFX_CMDHANDLERINFO* pHandlerInfo);

#ifndef _AFX_NO_OLE_SUPPORT
	// called when last OLE reference is released
	virtual void OnFinalRelease();
#endif

#ifndef _AFX_NO_OLE_SUPPORT
	// called before dispatching to an automation handler function
	virtual BOOL IsInvokeAllowed(DISPID dispid);
#endif

#ifndef _AFX_NO_OLE_SUPPORT
	// support for OLE type libraries
	void EnableTypeLib();
	HRESULT GetTypeInfoOfGuid(LCID lcid, const GUID& guid,
		LPTYPEINFO* ppTypeInfo);
	virtual BOOL GetDispatchIID(IID* pIID);
	virtual UINT GetTypeInfoCount();
	virtual CTypeLibCache* GetTypeLibCache();
	virtual HRESULT GetTypeLib(LCID lcid, LPTYPELIB* ppTypeLib);
#endif

// Implementation
public:
	virtual ~CCmdTarget() = 0;
#ifdef _DEBUG
	virtual void Dump(CDumpContext& dc) const;
	virtual void AssertValid() const;
#endif
#ifndef _AFX_NO_OLE_SUPPORT
	void GetNotSupported();
	void SetNotSupported();
#endif

protected:
	friend class CView;

	CView* GetRoutingView();
	CFrameWnd* GetRoutingFrame();
	static CView* PASCAL GetRoutingView_();
	static CFrameWnd* PASCAL GetRoutingFrame_();
	DECLARE_MESSAGE_MAP()       // base class - no {{ }} macros

#ifndef _AFX_NO_DOCOBJECT_SUPPORT
	DECLARE_OLECMD_MAP()
	friend class COleCmdUI;
#endif

#ifndef _AFX_NO_OLE_SUPPORT
	DECLARE_DISPATCH_MAP()
	DECLARE_CONNECTION_MAP()
	DECLARE_INTERFACE_MAP()

#ifndef _AFX_NO_OCC_SUPPORT
	DECLARE_EVENTSINK_MAP()
#endif // !_AFX_NO_OCC_SUPPORT

	// OLE interface map implementation
public:
	// data used when CCmdTarget is made OLE aware
	long m_dwRef;
	LPUNKNOWN m_pOuterUnknown;  // external controlling unknown if != NULL
	DWORD_PTR m_xInnerUnknown;  // place-holder for inner controlling unknown

public:
	// advanced operations
	void EnableAggregation();       // call to enable aggregation
	void ExternalDisconnect();      // forcibly disconnect
	LPUNKNOWN GetControllingUnknown();
		// get controlling IUnknown for aggregate creation

	// these versions do not delegate to m_pOuterUnknown
	DWORD InternalQueryInterface(const void*, LPVOID* ppvObj);
	DWORD InternalAddRef();
	DWORD InternalRelease();
	// these versions delegate to m_pOuterUnknown
	DWORD ExternalQueryInterface(const void*, LPVOID* ppvObj);
	DWORD ExternalAddRef();
	DWORD ExternalRelease();

	// implementation helpers
	LPUNKNOWN GetInterface(const void*);
	LPUNKNOWN QueryAggregates(const void*);

	// advanced overrideables for implementation
	virtual BOOL OnCreateAggregates();
	virtual LPUNKNOWN GetInterfaceHook(const void*);

	// OLE automation implementation
public:
	// OLE event sink implementation
	BOOL OnEvent(UINT idCtrl, AFX_EVENT* pEvent,
		AFX_CMDHANDLERINFO* pHandlerInfo);

#endif //!_AFX_NO_OLE_SUPPORT
};