COM连接点问题
网上下载到一个接收COM组件事件的例子,接收类是从CCmdTarget继承下来的
Advise时看到是这样写的
IUnknown* pUnknownSink = GetInterface(&IID_IUnknown);
m_pConnectionPoint->Advise(pSink, &m_AdviseCookie)
然后通过
BEGIN_DISPATCH_MAP(EventSink, CCmdTarget)
DISP_FUNCTION(EventSink, "Startup",OnAppStartup,VT_EMPTY,VTS_NONE)
END_DISPATCH_MAP()
来接收Startup事件映射到函数OnAppStartup
试了还挺正常,但这句不理解
IUnknown* pUnknownSink = GetInterface(&IID_IUnknown);
IID_IUnknown在unknown.h里,这样取出来的到底是什么?好像msdn上查做sink时都是从IDispatch继承类下来处理,不理解这个,请大家指教