public ActionResult DownloadExcel() { BusinessLayer BAL = new BusinessLayer(); var workbook = new Spire.Xls.Workbook(); workbook.LoadFromFile(Server.MapPath("~/DetailFormatInExcel/DetailsFormat.xlsx")); var worksheet1 = workbook.Worksheets[0]; var worksheet2 = workbook.Worksheets[1]; byte[] array = null; var dt1 = BAL.GetXlsTableBooks(); worksheet1.InsertDataTable(dt1, false, 3, 1); var dt2 = BAL.GetXlsTableCourse(); worksheet2.InsertDataTable(dt2, false, 3, 1); var dt3 = BAL.GetXlsTableTeacher(); worksheet2.InsertDataTable(dt3, false, 3, 3); using (var ms = new System.IO.MemoryStream()) { workbook.SaveToStream(ms, FileFormat.Version2010); ms.Seek(0, System.IO.SeekOrigin.Begin); array = ms.ToArray(); } return(File(array, "application / vnd.openxmlformats - officedocument.spreadsheetml.sheet", " Detail.xlsx")); }