title: WPF IEnumerable<T> vs IQueryable<T> as DataSource
body: <p>I have a <strong>WPF ListView</strong> and I bind it to a <code>IEnumerable&lt;T&gt;</code> collection.
  Everything works fine, but when I bind it to the <code>IQueryable&lt;T&gt;</code> collection, there are no items in list anymore.. Why? Is it not <strong>observable</strong> or what?
  When I look at the definition:</p>
  
  <pre><code>public interface IQueryable&lt;T&gt; : IEnumerable&lt;T&gt;, IQueryable, IEnumerable
  </code></pre>
  
  <p>and </p>
  
  <pre><code>public interface IEnumerable&lt;T&gt; : IEnumerable
  </code></pre>
  
  <p>so where is the problem?</p>