title: Code for adding to IEnumerable
body: <p>I have an enumerator like this</p>
  
  <pre><code>IEnumerable&lt;System.Windows.Documents.FixedPage&gt; page;
  </code></pre>
  
  <p>How can I add a page (eg: D:\newfile.txt) to it? I have tried <code>Add</code>, <code>Append</code>, <code>Concat</code> etc But nothing worked for me.</p>