I've got a controller action that returns a FileResult like this

return this.File("file.pdf", "application/pdf");

for the URL "/Download/322" - where 322 is the id of the file.

This works great, so that if a user clicks on a link to the PDF - it will open in their web browser as long as they have a PDF plugin installed.

But, what if they right-click the link and choose "Save as..."? The browser pops up with the filename as "322." I'd like to have a better filename at this point, by doing something like this:

return this.File("file.pdf", "application/pdf", "file.pdf");

But if I change the controller to return like that, then it will always pop up the download box, since MVC is setting the Content-Disposition header to attachment (so I can't embed the file).

In summary, can I somehow detect that the user is trying to download the file vs. the file is just being embedded in something on the page?