title: Checkbox for nullable boolean
body: <p>My model has a boolean that has to be nullable</p>
  
  <pre><code>public bool? Foo
  {
     get;
     set;
  }
  </code></pre>
  
  <p>so in my Razor cshtml I have</p>
  
  <pre><code>@Html.CheckBoxFor(m =&gt; m.Foo)
  </code></pre>
  
  <p>except that doesn't work. Neither does casting it with (bool). If I do</p>
  
  <pre><code>@Html.CheckBoxFor(m =&gt; m.Foo.Value)
  </code></pre>
  
  <p>that doesn't create an error, but it doesn't bind to my model when posted and foo is set to null. Whats the best way to display Foo on the page and make it bind to my model on a post?</p>