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
};