title: MVC5 comparing two nullable dates with fluent validation
body: <p>How can I write a rule in fluent validation to check two nullable dates in that the start date needs to be earlier than the end date.   </p>
  
  <p>I am thinking along the line of </p>
  
  <pre><code>RuleFor(c =&gt; c.StartDate)
              .NotEmpty()
  </code></pre>
  
  <p>if the start date is not empty and end date not empty then compare</p>