title: How to serialize property of type Object with XmlSerializer
body: <p>I have a property:</p>
  
  <pre><code>public object Tag
  </code></pre>
  
  <p>but it can contain finite number of types, unfortunately without base type (except object type). But when I serialize the object with this property, it doesn't get serialized. Is there a way to instruct XmlSerializer with possible types?</p>