title: Asp.Net MVC validation annotation regular expression attribute
body: <p>When I have a checkbox in my form it is not enough to mark the matching property as Required because a true or false is sent as it's value.</p>
  
  <p>Whats the best way to validate this in the model? I was thinking a regular expression to match the string true but I am either not writing it correctly or it does not work on a Boolean property.</p>
  
  <pre><code>public bool FeeAgree
      {
          get
          {
              return _feeAgree;
          }
          set
          {
              _feeAgree = value;
          }
      }
  </code></pre>
  
  <p>Above is the property I am trying to validate. Using the Required attribute does not work because the Html.CheckBoxFor creates a hidden field so there is always a valueof either true or false passed.</p>