COM中的可连接对象与连接点机制及其MFC程序实现(3)

　　3.添加基类为CCmdTarget的类CConnObject.在类声明文件CConnObject1.h中加上#include “IConnObject.h”,在类声明中写入:

protected:

……

//声明实现IEventServer接口的嵌套类

BEGIN_INTERFACE_PART(EventServer,IEventServer)

STDMETHOD(DoSomething)();

END_INTERFACE_PART(EventServer)

DECLARE_INTERFACE_MAP()

//声明实现连接点的嵌套类

BEGIN_CONNECTION_PART(CConnObject,SampleConnPoint)

CONNECTION_IID(IID_IEventSink)

END_CONNECTION_PART(SampleConnPoint)

DECLARE_CONNECTION_MAP()

DECLARE_OLECREATE(CConnObject) 

　　说明:BEGIN_CONNECTION_PART和END_CONNECTION_PART宏声明了实现连接点的嵌套类SampleConnPoint,并且是基于CConnectionPoint类的,如果需要重载CConnectionPoint类的成员函数或者添加自己的成员函数,可以在这两个宏中声明.这里,CONNECTION_IID宏重载了CConnectionPoint::GetIID()函数.使用DECLARE_CONNECTION-MAP()宏声明连接点映射表.

　　4.在类CConnObject的实现文件中写入

IMPLEMENT_OLECREATE(CConnObject,"ConnObject",

0xee888b01, 0xea9c, 0x11d3, 0x97, 0xb5, 0x52, 0x54, 0xab, 0x19, 0x19, 0x30);

BEGIN_INTERFACE_MAP(CConnObject,CCmdTarget)

INTERFACE_PART(CConnObject,IID_IEventServer,EventServer)

INTERFACE_PART(CConnObject,IID_IConnectionPointContainer,ConnPtContainer)

END_INTERFACE_MAP()

BEGIN_CONNECTION_MAP(CConnObject,CCmdTarget)

CONNECTION_PART(CConnObject,IID_IEventSink,SampleConnPoint)

END_CONNECTION_MAP()

说明:A.必须在接口映射中写入INTERFACE_PART(CConnObject,IID_IConnectionPointContainer,ConnPtContainer)以实现IConnectionPointContainer接口.注意,CCmdTarget类内嵌有才ConnPtContainer类以实现IConnectionPointContainer接口,并用m_xConnPtContainer加以记录.

B.用BEGIN_CONNECTION_MAP和END_CONNECTION_MAP宏实现连接点映射.CONNECTION_PART定义了实现连接点的类.