title: Adding to Collection when Collection is Null
body: <p>I keep getting a null ref on the Children List when trying to add to the list via my property below</p>
  
  <pre><code>    public class Node&lt;T&gt; where T : INode
      {
          private readonly T _item;
  
          public IList&lt;Node&lt;T&gt;&gt; Children { get; set; } 
  
          public Node(T item)
          {
              _item = item;
              ParentNodeId = item.ParentNodeId;
          }
  
  
          public void AddChild(T childNode)
          {
              Children.Add(new Node&lt;T&gt;(childNode));
          }
  ....
  </code></pre>
  
  <p>And I wouldn't think you want to initiate the Children list every time it hits this property so what should I do to be able to add to this Node's children every time the calling code needs to populate it?</p>