title: cannot implicitly convert type 'bool?' to 'bool'. An explicit conversion exists (are you missing a cast?)
body: <blockquote>
    <p>Error : cannot implicitly convert type 'bool?' to 'bool'. An explicit
    conversion exists (are you missing a cast?)</p>
  </blockquote>
  
  <p>Code :</p>
  
  <pre><code>Test obj = new Test();
  obj.IsDisplay = chkDisplay.IsChecked;
  </code></pre>
  
  <p>but when I use this method to cast the property into a bool then there is no error.</p>
  
  <pre><code>Test obj = new Test();
  obj.IsDisplay = (bool) chkDisplay.IsChecked;
  </code></pre>
  
  <p>I would like to know why I need to cast this bool to bool?</p>