title: Indeterminate state of check box
body: <p>I have a check box in WPF and I want to set it to the indeterminate state. How can I do that? Is there a way to set it like :</p>
  
  <pre><code>CheckBox.State=CheckBoxStates.TriState;
  </code></pre>
  
  <p>Or is there some other way to do that?</p>
  
  <p>Also is it possible to change the visual look of the checkbox as :</p>
  
  <ul>
  <li>☑ for checked</li>
  <li>☒ for unchecked</li>
  <li>☐ for indeterminate state 
  or I will have to create a custom control?</li>
  </ul>