public void Export() { HttpResponse Response = System.Web.HttpContext.Current.Response; // Load your source workbook Workbook workbook = new Workbook(); // Creating a Workbook object var sheet = workbook.Worksheets[0]; sheet.Cells[0, 0].PutValue(1); if (Response != null) { // Save in Xlsx format workbook.Save(Response, "test.xlsx", ContentDisposition.Attachment, new OoxmlSaveOptions()); Response.End(); } }