title: How do I return a FileResult in ASP.NET without knowing the MIME type?
body: <p>My ASP.NET MVC application has pages with attachments and these attachments can be of many different file types.</p>
  
  <p>When the user then wants to access their attachment, I need to fire off an FileResult and return the file attachment which I have the path to.</p>
  
  <p>However, I have no database of mime-types, nor do I know off-hand the mime-type of these files off hand.</p>
  
  <p>What is the proper way to handle this?  Is there a way I can return a file and let the framework attempt to figure out the mimetype?</p>
  
  <p>Any suggestions?</p>