sender, EventArgs e) { FileStream file = new FileStream(Server.MapPath("template/") + "a.xls", FileMode.Open, FileAccess.Read); HSSFWorkbook hssfworkbook = new HSSFWorkbook(file); file.Close(); ISheet sheet1 = hssfworkbook.GetSheet("Sheet1"); if (sheet1.GetRow(23) == null) { sheet1.CreateRow(23); } if (sheet1.GetRow(23).GetCell(6) == null) { sheet1.GetRow(23).CreateCell(6); } sheet1.GetRow(23).GetCell(6).SetCellValue(300); sheet1.ForceFormulaRecalculation = true; FileStream file2 = new FileStream(Server.MapPath("template/") + "ccc.xls", FileMode.Create, FileAccess.Write); hssfworkbook.Write(file2); file2.Close(); }