title: Adding an item to IEnumerable
body: <p>I had a List&lt;> of my objects, but now need to change it to an IEnumerable&lt;>. So, I have this:</p>
  
  <pre><code>public IEnumerable&lt;TransactionSplitLine&gt; TransactionSplitLines { get; set; }
  </code></pre>
  
  <p>However, I can no longer do:</p>
  
  <pre><code>reply.TransactionSplitLines.Add(new TransactionSplitLine
                                                      {Amount = "100", Category = "Test", SubCategory = "Test More", CategoryId=int.Parse(c)});
  </code></pre>
  
  <p>How should I be adding items now?</p>