if Savedialog2.Execute then begin
  if extractfileext(savedialog2.FileName) = '.xls' then XLSFile := TXLSExport.Create(Savedialog2.FileName)
  else XLSFile := TXLSExport.Create(Savedialog2.FileName + '.xls');
    try
      for iRow := 0 to StringGrid1.RowCount - 1 do
      for iCol := 0 to StringGrid1.ColCount - 1 do
      if iRow = 0 then // Ausgabe Spaltenköpfe als string
        xlsfile.Write(iCol, iRow, StringGrid1.Cells[iCol, iRow])
      else // der Rest sind integer Werte
        xlsfile.Write(iCol, iRow, (*StrToInt*)(StringGrid1.Cells[iCol,iRow]));
    finally
      xlsfile.Free;
    end;
  Showmessage(Savedialog2.FileName + '.xls was created');