FileStream file = new FileStream(Server.MapPath(@"TemFiles\2.xls"), FileMode.Open, FileAccess.Read);            HSSFWorkbook workbook = new HSSFWorkbook(file);            ISheet sheet1 = workbook.GetSheetAt(0);            IRow row1 = sheet1.CreateRow(0);            row1.CreateCell(0).SetCellValue(1);                      sheet1.CreateRow(0).CreateCell(0).SetCellValue("This　is　a　Sample");            sheet1.GetRow(0).CreateCell(0).SetCellValue("This　is　a　Sample");            MemoryStream msfile = new MemoryStream();             workbook.Write(msfile);            Response.ContentEncoding = System.Text.Encoding.UTF8;            Response.ContentType = "application/octet-stream";            var fileName = HttpUtility.UrlEncode("2");            Response.AppendHeader("Content-Disposition", "attachment; filename=" + fileName + ".xls");            Response.BinaryWrite(msfile.GetBuffer());