title: Serialize an object using DataContractJsonSerializer as a json array
body: <p>I have a class which contains a list of items. 
  I want to serialize an instance of this class to json using the DataContractJsonSerializer as a json array. eg.</p>
  
  <pre><code>class MyClass 
  {
      List&lt;MyItem&gt; _items;
  }
  
  class MyItem
  {
     public string Name {get;set;}
     public string Description {get;set;}
  }
  </code></pre>
  
  <p>When serialized to json it should be like this : </p>
  
  <p><code>[{"Name":"one","Description":"desc1"},{"Name":"two","Description":"desc2"}]</code></p>