关于接口使用的问题

Question

我创建了一个atl控件
在_i.c 文件中有
const IID LIBID_SPEMGRDLib = {0x752F2474,0xEAE0,0x48ea,{0xBF,0xDD,0xA5,0x36,0xBA,0x66,0x12,0x3E}};const IID IID_IColumn = {0xA44DE163,0x50A5,0x43d2,{0x86,0xDA,0x35,0x43,0x49,0x19,0x3B,0xB7}};const IID IID_ISpemGrid = {0xA681A701,0xF4F3,0x480e,{0xAF,0x64,0x44,0x94,0xC4,0x36,0xDA,0x5C}};const CLSID CLSID_SpemGrid = {0x04D489F1,0xFB07,0x4541,{0xA5,0x74,0xE9,0x57,0xA9,0x9A,0x89,0x61}};interface IColumn : IUnknown 
interface ISpemGrid : IDispatch在vb中这样 Dim c As SPEMGRDLibCtl.IColumn 就可以得到IColumn接口
不知道在vc中如何创建这个接口？
ISpemGrid *pISpemGrid;
hr=::CoCreateInstance( CLSID_SpemGrid,NULL,CLSCTX_INPROC_SERVER,IID_ISpemGrid,(void **)&pISpemGrid );
这句能够成功，但IColumn *pIColumn;
hr=::CoCreateInstance( CLSID_SpemGrid,NULL,CLSCTX_INPROC_SERVER,IID_IColumn,(void **)&pIColumn );
却执行失败，不知得到该接口是不是这样写？

Answer 1

试试将CLSCTX_INPROC_SERVER改成CLSCTX_SERVER...

Answer 2

pISpemGrid->QueryInterface(IID_IColumn,(void **)&pIColumn);