title: How to add Assembly reference?
body: <p>I added <code>using Microsoft.VisualBasic</code> to my code but compiler reports error CS0234:</p>
  
  <blockquote>
    <p>The type or namespace name 'FileSystem' does not exist in the namespace 'Microsoft.VisualBasic' (are you missing an assembly reference?)</p>
  </blockquote>
  
  <p>What is this "assembly reference" and how to add one?</p>
  
  <p>Error also shown in the picture
    <a href="http://img16.imageshack.us/img16/6517/errorcup.jpg" rel="nofollow">http://img16.imageshack.us/img16/6517/errorcup.jpg</a></p>