title: How to catch HttpRequestValidationException
body: <p>How can i redirect the user to a custom error page, when HttpRequestValidationException occurred.
  I tried to catch it in my basecontroller :</p>
  
  <pre><code>protected override void OnException(ExceptionContext exceptionContext)
      {
        if (exceptionContext.Exception is HttpRequestValidationException)
          {
            this.View("CustomError").ExecuteResult(this.ControllerContext);
          }
      }
  </code></pre>
  
  <p>But i still get the exception :
  A potentially dangerous request.form value was detected from the client</p>