这种方法回报一个Error!
D:\Program Files\Microsoft Visual Studio\VC98\INCLUDE\comip.h(690) : error C2227: left of '->QueryInterface' must point to class/struct/union
D:\Program Files\Microsoft Visual Studio\VC98\INCLUDE\comip.h(75) : see reference to function template instantiation 'long __thiscall _com_ptr_t<class _com_IIID<struct MSXML2::IXMLDOMNode,&struct __s_GUID _GUID_2933bf80_7b36_11d2_b20e_00c04
f983e60> >::_QueryInterface(void *const & )' being compiled