DATAGRID控件的问题

请帮忙看看以下代码绑定数据源后为什么结果集无输出，谢谢！
_ConnectionPtr m_pConnection;

_RecordsetPtr m_pRecordset;

try
{
m_pConnection.CreateInstance(__uuidof(Connection));
m_pConnection->Open("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=Northwind.mdb","","",adModeUnknown);
}
catch(_com_error e)
{
CString errormessage;
errormessage.Format("连接数据库失败!\r错误信息:%s",e.ErrorMessage());
AfxMessageBox(errormessage);
return;
}

try
{
m_pRecordset.CreateInstance("ADODB.Recordset"); 
m_pRecordset->Open("SELECT * FROM Employees",
_variant_t((IDispatch*)m_pConnection,true),
adOpenStatic,
adLockOptimistic,
adCmdText);
}
catch(_com_error &e)
{
AfxMessageBox(e.Description());
}

m_ctrlDataGrid.SetRefDataSource(NULL);
m_ctrlDataGrid.SetRefDataSource((LPUNKNOWN)m_pRecordset);

m_pRecordset->Close();
m_pRecordset=NULL;
m_pConnection->Close();
m_pConnection=NULL;
}