Your action method should ideally return FileResult or ActionResult to allow the MVC framework to handle the response headers correctly.
public ActionResult DownloadExcel() { // 1. Generate or retrieve your byte array byte[] fileBytes = GetExcelByteArray(); // 2. Define the content type for Excel (.xlsx) string contentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"; // 3. Define the download file name string fileName = "Report.xlsx"; // 4. Return the file return File(fileBytes, contentType, fileName); } Use code with caution. 2. Generating the Byte Array
using (var package = new ExcelPackage()) { var sheet = package.Workbook.Worksheets.Add("MySheet"); sheet.Cells["A1"].Value = "Hello World"; // Convert the package to a byte array return package.GetAsByteArray(); } Use code with caution. download excel file from byte array c# mvc
If you are creating the Excel file dynamically, you will typically use a MemoryStream to capture the workbook data and then convert it to an array.
For modern .xlsx files, use application/vnd.openxmlformats-officedocument.spreadsheetml.sheet . For older .xls files, use application/vnd.ms-excel . Your action method should ideally return FileResult or
using (var workbook = new XLWorkbook()) { var worksheet = workbook.Worksheets.Add("Sample Sheet"); worksheet.Cell("A1").Value = "Data Content"; using (var stream = new MemoryStream()) { workbook.SaveAs(stream); return stream.ToArray(); // Returns the byte array } } Use code with caution. Key Components for Success
To download an Excel file from a byte array in C# ASP.NET MVC, you primarily use the File method within a controller action to return a FileContentResult . This approach is efficient for files generated in memory using libraries like EPPlus or ClosedXML . Implementation Guide 1. Controller Action Setup Define the content type for Excel (
The most direct way to trigger a download is by returning a File object that takes the byte array, the MIME type, and the desired file name.
Use a standard HTML link or a form submission. Note that AJAX requests do not naturally trigger browser "Save As" dialogs; for AJAX, you may need to create a Blob object in JavaScript to handle the download on the client side. Summary Table: Common Download Methods Requirement Method to Use Return Type From Byte Array File(byteArray, contentType, fileName) FileContentResult From Stream File(fileStream, contentType, fileName) FileStreamResult From Local Path File(filePath, contentType, fileName) FilePathResult Return Excel File from Controller in ASP.Net MVC