Force browser to download PDF document instead of opening it

If you want to render the file(s) so that you could save them at your end instead of opening in the browser, you may try the following code snippet:

//create new MemoryStream object and add PDF file’s content to outStream.
MemoryStream outStream = new MemoryStream();

//specify the duration of time before a page cached on a browser expires
Response.Expires = 0;

//specify the property to buffer the output page
Response.Buffer = true;

//erase any buffered HTML output
Response.ClearContent();

//add a new HTML header and value to the Response sent to the client
Response.AddHeader(“content-disposition”, “inline; filename=” + “output.pdf”);

//specify the HTTP content type for Response as Pdf
Response.ContentType = “application/pdf”;

//write specified information of current HTTP output to Byte array
Response.BinaryWrite(outStream.ToArray());

//close the output stream
outStream.Close();

//end the processing of the current page to ensure that no other HTML content is sent
Response.End();

However, if you want to download the file using a client application then you'll have to use the WebClient class.

You should look at the "Content-Disposition" header; for example setting "Content-Disposition" to "attachment; filename=foo.pdf" will prompt the user (typically) with a "Save as: foo.pdf" dialog, rather than opening it. This, however, needs to come from the request that is doing the download, so you can't do this during a redirect. However, ASP.NET offers Response.TransmitFile for this purpose. For example (assuming you aren't using MVC, which has other preferred options):

Response.Clear();
Response.ContentType = "application/pdf";
Response.AppendHeader("Content-Disposition", "attachment; filename=foo.pdf");
Response.TransmitFile(filePath);
Response.End();