title: LINQ OrderByDescending passing a string value
body: <p>Hi I am trying to <code>OrderByDescending()</code> on a query but rather than:</p>
  
  <pre><code>results = results.OrderByDescending(o =&gt; o.Surname);  
  </code></pre>
  
  <p>I wish to use:</p>
  
  <pre><code>results = results.OrderByDescending(o =&gt; "Surname");  
  </code></pre>
  
  <p>The value in quotes would be passed in in a parameter.   </p>
  
  <p>I was looking at reflection but am unsure. </p>