title: Get Item From List<T> and update a property on that Item
body: <p>I have a List of type Person that I would like to update DisplayValue based on DisplayName.  How can I accomplish this?</p>
  
  <pre><code>public class Person
  {
       public string DisplayName { get; set; }
       public string DisplayValue { get; set; }
       ... other properties
  }
  </code></pre>