Delphi7 TClientDataSet作为内存数据集合使用

procedure TMainForm.btnExportClick(Sender: TObject);
  tmpCds:TClientDataSet;
  tmpStr:string;
begin

   //TClientDataSet作为内存数据集合使用
  //***************************************************
  try
  tmpCds := TClientDataSet.Create(Application);
  if(tmpCds<>nil) then
    begin
      tmpCds.FieldDefs.Add('col1', ftString,10);
      tmpCds.FieldDefs.Add('col2', ftString,10);
      tmpCds.CreateDataSet;
//插入数据
      with tmpCds do
      begin
        Insert;
        fieldbyname('col1').AsString := '总行程：';
        fieldbyname('col2').AsString := FormatFloat('#.##',yearStat.getyearMiles());

        next;
        insert;
        fieldbyname('col1').AsString := '总加油量：';
        fieldbyname('col2').AsString := FormatFloat('#.##',yearStat.gettotalOilBuy());

        next;
        insert;
        fieldbyname('col1').AsString := '总平均油耗：';
        fieldbyname('col2').AsString := FormatFloat('#.##',yearStat.getyearAvgOilExpense());

      end;
      tmpCds.Post;

//读取数据
       with tmpCds do
       begin
        open;
        first;
        while not tmpCds.Eof do
        begin
          tmpStr := fields[0].Value;
          OutputDebugString(PChar(tmpStr));
          tmpStr := fields[1].Value;
          OutputDebugString(PChar(tmpStr));  
          next;
        end;

       end;

    end;
  finally
    tmpCds.Free;
  end;
end;