title: How can I get my CheckBoxList to have three possible states?
body: <p>How can I get my <code>CheckBoxList</code> to have three possible states ? More precisely, is there a way to have three possible states for each checkbox : checked, unchecked, undefined (in most GUIs this is represented as a full square).</p>
  
  <p>Alternatively, do you recommend another control that would meet these needs ?</p>
  
  <p><strong>UPDATE</strong> : Ok, given that HTML does not support tri-state checkboxes, I'm looking for a way to 'CSS' (color fill, highlight, etc...) the checkboxes of the items that are in that 'undefined' state from my server point of view. </p>