Windows Update 中的 IID_IDownloadProgressChangedCallback 接口

[罗嘉贇]

IID_IDownloadProgressChangedCallback 这个接口是在哪里。为什么我无法获取。我的代码是

         HRESULT hRes;
	IUnknown * pUnknow = NULL;
	hRes = CoCreateInstance ( CLSID_UpdateSession, NULL, CLSCTX_INPROC_SERVER | CLSCTX_LOCAL_SERVER,     IID_IUnknown ,( void ** ) & pUnknow);
         hRes = pUnknow->QueryInterface(IID_IDownloadProgressChangedCallback , (void**)&m_pDownloadProgressChangedCallback);

[oyljerry]

http://msdn.microsoft.com/en-us/library/aa387292(VS.85).aspx