public IActionResult Export() { using (var mstream = new MemoryStream()) { using (var stream = _managementService.Download(_fees.GetDataTable())) { stream.Seek(0, SeekOrigin.Begin); stream.CopyTo(mstream); } return(new FileContentResult(mstream.ToArray(), "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet")); } }