title: Add list of items to another object as a list where two values are equal
body: <p>I have 2 objects as below:</p>
  
  <pre><code>public class object1
  {
      public int Object1ID { get; set; }
      public string SomeValue { get; set; }
      public List&lt;object2&gt; ListOfObject2 { get; set; }
  }
  
  public class object2
  {
      public int Object2ID { get; set; }
      public string SomeValue2 { get; set; }
      public int Object1LinkedID { get; set; }
  }
  </code></pre>
  
  <p>Object1ID and Object2ID are unique ids.</p>
  
  <p>I populate both of them as lists (so I have a list of Object1s and a list of Object2s).</p>
  
  <pre><code>List&lt;Object1&gt; listObject1 = new List&lt;Object1&gt;();
  List&lt;Object2&gt; listObject2 = new List&lt;Object2&gt;();
  </code></pre>
  
  <p>I'd like to add all of the Object2s to Object1 where <code>Object1LinkedID</code> is equal to <code>Object1</code>. This can be into a new Object or just an update to original Object1 list. </p>