title: How can I filter a List with linq based on a value of a list within?
body: <p>I have a model that has a list of a list:
  List 1 = States
  List 2 = Zip Codes</p>
  
  <p>Zip Codes has a property that sees if it's been checked (bool) &amp; I am displaying all the states and a list of zip codes they could select the zip codes from a list of checkboxes and when the model gets posted back on HttpPost then checked gets set to true.</p>
  
  <p>I need to filter the list of states to pull back only the states that have zip codes checked. I tried this but it comes back null:</p>
  
  <pre><code>var temp = States.Where(a =&gt; a.ZipCodes.Where(b =&gt; b.Checked == true).Any()).ToList();
  </code></pre>