在ADO方式访问Excel时，需要注意几个问题：
1）新旧格式Excel（xls和xlsx）访问ado字符串的区别
2）获得多表单（sheet）的表单名

    if(connXLS->Connected)
        connXLS->Connected = false;
 
    if(CompareStr(sFileExtName, "xls")==0)
    {
        sConnectString = "Provider=Microsoft.Jet.OLEDB.4.0;Extended Properties=Excel 8.0;Persist Security Info=false;Data Source="
                                   + sXlsFileName;
        //2003（Microsoft.Jet.Oledb.4.0）
        //string strConn = string.Format("Provider=Microsoft.Jet.OLEDB.4.0;Data Source={0};Extended Properties='Excel 8.0;HDR=Yes;IMEX=1;'", excelFilePath);
    }else{
        sConnectString = "Provider=Microsoft.ACE.OLEDB.12.0;Extended Properties='Excel 8.0;HDR=YES;IMEX=1';Persist Security Info=false;Data Source="
                                   + sXlsFileName;    
        //2007（Microsoft.ACE.OLEDB.12.0）
        //string strConn = string.Format("Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};Extended Properties='Excel 8.0;HDR=Yes;IMEX=1;'", excelFilePath);                           
    }        
 
    connXLS->ConnectionString = sConnectString;
    adoXLS->Connection = connXLS;
    try
    {
        AnsiString sTableName;
        OleVariant EmptyParam = varEmpty;  
        EmptyParam.VType = VT_ERROR;
        EmptyParam.VError = DISP_E_PARAMNOTFOUND;
 
        auto_ptr<TADOQuery> query(new TADOQuery(NULL));
        query->Connection = connXLS;
        connXLS->OpenSchema(siTables, EmptyParam, EmptyParam, (TADODataSet*)query.get());
 
        for ( ; !query->Eof; query->Next() )
        {
            sTableName = query->FieldByName("TABLE_NAME")->AsString;
            printscreen("当前Excel %s", sTableName.c_str());
        }  
 
        if(adoXLS->Active)
            adoXLS->Close();
        adoXLS->TableName = sTableName;
        adoXLS->Open();
    }catch(Exception &exception){
        ShowMessage(exception.Message);
        return;
    }