title: Check if property is null in lambda expression
body: <p>I have a list of objects that I am trying to bind to a listview. I am sorting by two properties. The problem exists whereby some records may not have one of the properties. This is causing an error. I would like it to still bind the records that have the property.</p>
  
  <pre><code>IEnumerable&lt;ERec&gt; list = retailerList.Cast&lt;ERec&gt;();
  lvwRetailStores.DataSource = list.OrderByDescending(r =&gt; r.Properties["RS_Partner Type"].ToString())
                                   .ThenBy(r =&gt; r.Properties["RS_Title"].ToString());
  </code></pre>