title: C# - Encoding.ASCII.GetString() returns "??" instead of actual string, why?
body: <p>This is my piece of code (file is a <code>HttpPostedFileBase</code> type):</p>
  
  <pre><code>var imageStream = file.InputStream;
  var header = new Byte[4];
  imageStream.Read(header, 0, header.Length);
  </code></pre>
  
  <p>Now, while my code runs, i place a breakpoint, and in my immediate window i check values:</p>
  
  <pre><code>header
  {byte[4]}
      [0]: 255
      [1]: 216
      [2]: 255
      [3]: 224
  </code></pre>
  
  <p>But, when i want to convert this byte array to string of ASCII, i get this (values obtained by immediate window):</p>
  
  <pre><code>Encoding.ASCII.GetString(header)
  "????"
  Encoding.ASCII.GetString(header, 0, 2)
  "??"
  </code></pre>
  
  <p>What am I doing wrong?</p>