How can I present a file for download from an MVC controller

Question

In WebForms  I would normally have code like this to let the browser present a  Download File  popup with an arbitrary file type  like a PDF  and a filename   Response Clear   Response ClearHeaders       Send the file to the output stream Response Buffer   True  Response AddHeader  Content-Length   pdfData Length ToString    Response AddHeader  Content-Disposition    attachment  filename     amp  Server HtmlEncode filename        Set the output stream to the correct content type  PDF   Response ContentType    application pdf       Output the file Response BinaryWrite pdfData       Flushing the Response to display the serialized data     to the client browser  Response Flush   Response End     How do I accomplish the same task in ASP NET MVC

User · Answer

To force the download of a PDF file  instead of being handled by the browser s PDF plugin   public ActionResult DownloadPDF         return File    Content MyFile pdf    application pdf    MyRenamedFile pdf        If you want to let the browser handle by its default behavior  plugin or download   just send two parameters   public ActionResult DownloadPDF         return File    Content MyFile pdf    application pdf        You ll need to use the third parameter to specify a name for the file on the browser dialog   UPDATE  Charlino is right  when passing the third parameter  download filename  Content-Disposition  attachment  gets added to the Http Response Header  My solution was to send application force-download as the mime-type  but this generates a problem with the filename of the download so the third parameter is required to send a good filename  therefore eliminating the need to force a download

User · Answer

Although standard action results FileContentResult or FileStreamResult may be used for downloading files  for reusability  creating a custom action result might be the best solution   As an example let s create a custom action result for exporting data to Excel files on the fly for download   ExcelResult class inherits abstract ActionResult class and overrides the ExecuteResult method   We are using FastMember package for creating DataTable from IEnumerable object and ClosedXML package for creating Excel file from the DataTable   public class ExcelResult lt T gt    ActionResult       private DataTable dataTable      private string fileName       public ExcelResult IEnumerable lt T gt  data  string filename  string   columns                this dataTable   new DataTable            using  var reader   ObjectReader Create data  columns                         dataTable Load reader                     this fileName   filename             public override void ExecuteResult ControllerContext context                if  context    null                        var response   context HttpContext Response              response Clear                response ContentType    application vnd openxmlformats-officedocument spreadsheetml sheet               response AddHeader  content-disposition   string Format   attachment filename    0      fileName                using  XLWorkbook wb   new XLWorkbook                                  wb Worksheets Add dataTable   Sheet1                    using  MemoryStream stream   new MemoryStream                                          wb SaveAs stream                       response BinaryWrite stream ToArray                                                         In the Controller use the custom ExcelResult action result as follows   HttpGet  public async Task lt ExcelResult lt MyViewModel gt  gt  ExportToExcel         var model   new Models MyDataModel        var items   await model GetItems        string   columns   new string      Column1    Column2    Column3         string filename    mydata xlsx       return new ExcelResult lt MyViewModel gt  items  filename  columns       Since we are downloading the file using HttpGet  create an empty View without model and empty layout   Blog post about custom action result for downloading files that are created on the fly   https   acanozturk blogspot com 2019 03 custom-actionresult-for-files-in-aspnet html

User · Answer

Use  ashx file type and use the same code

User · Answer

You can do the same in Razor or in the Controller  like so             do this on the top most of your View  immediately after  using  statement     Response ContentType    application pdf       Response AddHeader  Content-Disposition    attachment  filename receipt pdf        Or in the Controller    public ActionResult Receipt         Response ContentType    application pdf       Response AddHeader  Content-Disposition    attachment  filename receipt pdf         return View        I tried this in Chrome and IE9  both is downloading the pdf file   I probably should add I am using RazorPDF to generate my PDFs  Here is a blog about it  http   nyveldt com blog post Introducing-RazorPDF

User · Answer

You should look at the File method of the Controller  This is exactly what it s for  It returns a FilePathResult instead of an ActionResult

User · Answer

mgnoonan   You can do this to return a FileStream        lt summary gt      Creates a new Excel spreadsheet based on a template using the NPOI library      The template is changed in memory and a copy of it is sent to     the user computer through a file stream       lt  summary gt       lt returns gt Excel report lt  returns gt   AcceptVerbs HttpVerbs Post   public ActionResult NPOICreate         try                  Opening the Excel template            FileStream fs               new FileStream Server MapPath    Content NPOITemplate xls    FileMode Open  FileAccess Read               Getting the complete workbook            HSSFWorkbook templateWorkbook   new HSSFWorkbook fs  true               Getting the worksheet by its name            HSSFSheet sheet   templateWorkbook GetSheet  Sheet1                Getting the row    0 is the first row          HSSFRow dataRow   sheet GetRow 4               Setting the value 77 at row 5 column 1         dataRow GetCell 0  SetCellValue 77               Forcing formula recalculation            sheet ForceFormulaRecalculation   true           MemoryStream ms   new MemoryStream                Writing the workbook content to the FileStream            templateWorkbook Write ms            TempData  Message      Excel report created successfully                Sending the server processed data back to the user computer            return File ms ToArray     application vnd ms-excel    NPOINewFile xls              catch Exception ex                TempData  Message      Oops  Something went wrong             return RedirectToAction  NPOI

User · Answer

Return a FileResult or FileStreamResult from your action  depending on whether the file exists or you create it on the fly   public ActionResult GetPdf string filename        return File filename   application pdf   Server UrlEncode filename

[asp.net-mvc] How can I present a file for download from an MVC controller?

Examples related to asp.net-mvc

Examples related to download