//如果是取容器接口指针
LPOLECONTAINER lpContainer;
HRESULT hr = m_pClientSite->GetContainer(&lpContainer);

//如果是取窗口句柄
HWND m_hWndParent;
IOleInPlaceSite *pOleInPlaceSite = NULL;
if (NOERROR==m_pClientSite->QueryInterface(IID_IOleInPlaceSite, (LPVOID *)&pOleInPlaceSite))
{
 pOleInPlaceSite->GetWindow((HWND *)&m_hWndParent);
 pOleInPlaceSite->Release();
}