Delphi操作Excel(Use Oel)

procedure TorderMore1.BitBtn2Click(Sender: TObject);
var
  xlsFile:WideString;
  var ExcelApp: Variant;
begin
  SaveDialog1.FileName:= MyQuery3.FieldValues[‘orderno‘] + ‘.xls‘;
  if SaveDialog1.Execute then
  begin
    xlsFile:=ExtractFilePath(application.ExeName)+‘xlsorder_detail.xls‘;
    ExcelApp := CreateOleObject(‘Excel.Application‘);
    ExcelApp.WorkBooks.Open(xlsFile);
    ExcelApp.ActiveWorkBook.SaveAs(SaveDialog1.FileName);
    ExcelApp.Cells[2].Value := ExcelApp.Cells[2].Value + VarToStr(MyQuery3.FieldValues[‘orderno‘]);
    if not ExcelApp.ActiveWorkBook.Saved then
      ExcelApp.ActiveWorkBook.Save;
    ExcelApp.Visible := True;
    //ExcelApp.ActiveWorkBook.Close;
    //ExcelApp.Quit;
    ExcelApp:=unassigned;
  end;
end;