各位大虾能不能帮小弟解决两个DirectShow编程的问题？谢了！

IGraphBuilder *pigb  = NULL;
IVideoWindow  *pivw  = NULL;// QueryInterface for some basic interfaces
pigb->QueryInterface(IID_IVideoWindow, (void **)&pivw);// Have the graph construct its the appropriate graph automatically
hr = pigb->RenderFile(wFile, NULL);pivw->put_Owner((OAHWND)ghApp);
pivw->put_WindowStyle(WS_CHILD|WS_CLIPSIBLINGS|WS_CLIPCHILDREN);