public FileStreamResult DownloadExcelFile(DataTable dt, string filename)
ExcelEngine excelEngine = new ExcelEngine();
IApplication application = excelEngine.Excel;
application.DefaultVersion = ExcelVersion.Excel2013;
IWorkbook workbook = application.Workbooks.Create(1);
IWorksheet worksheet = workbook.Worksheets[0];
string ContentType = "Application/msexcel";
MemoryStream memstream = new MemoryStream();
workbook.SaveAs(memstream);
return File(memstream, ContentType, filename);