title: How-To: Validate a FileStream is a valid PDF document with .NET
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/3108201/detect-if-pdf-file-is-correct-header-pdf">Detect if PDF file is correct (header PDF)</a>  </p>
  </blockquote>
  
  
  
  <p>I want to validate that the data in a <code>FileStream</code> instance represents a valid PDF document.  Specifically, I need to know that Adobe Reader will be able to successfully open the file.</p>
  
  <p>Can anyone recommend an open source library or best practice for this task?</p>