急,关于ado的一个傻问题,大侠救命!!!

Question

pUserSet->Open("select * from score",theApp.m_pConnection.GetInterFacePtr(),adOpenDynamic,adLockOptimistic,adCmdText);错误说:
error C2228: left of '.m_pConnection' must have class/struct/union type
error C2228: left of '.GetInterfacePtr' must have class/struct/union type
error C2664: 'Open' : cannot convert parameter 1 from 'class CString' to 'const class _variant_t &'
Reason: cannot convert from 'class CString' to 'const class _variant_t'
No constructor could take the source type, or constructor overload resolution was ambiguous
请问是什么原因啊,而且查了另外一本书也是这样用的啊

Answer 1

theApp.m_pConnection.GetInterFacePtr()
must change to:
theApp.m_pConnection->GetInterFacePtr()

Answer 2

_bstr_t strCnn("Provider=sqloledb;Data Source=MyServer;Initial Catalog=pubs;User Id=sa;Password=***;");
_bstr_t strRst("select * from score");
_ConnectionPtr m_pConnection;
_RecordSetPtr pUserSet;
try
{
  m_pConnection.CreateInstance(__uuidof(Connection));
  m_pConnection->Open(strCnn,"","",adConnectUnspecified);
  pUserSet.CreateInstance(__uuidof(RecordSet));
  pUserSet->Open(strRst,_variant_t((IDispatch *) m_pConnection, true),adOpenKeyset,adLockOptimistic,adCmdTable);
}
catch(_com_error &e)
   {
...............
}