title: LINQ Update or Insert objects into List
body: <p>Ok, so I have a List that contains a collection of message objects. An updated list of message objects comes in every 60 seconds. Some of the objects in the first collection will have updated data based on an ID property inside each object.</p>
  
  <pre><code>public class Message
  {
      public Int64 Id { get; set; }
      public string Property1 { get; set; }
      public DateTime MessageDate { get; set; }
  }
  </code></pre>
  
  <p>How in LINQ can I Insert in the updated object based on the Id?</p>