title: Silverlight RichtextBox Xaml Property, cannot set value (exception)
body: <p>Hi I want to set the Xaml property of my silverlight richtext box.        </p>
  
  <pre><code>this.Dispatcher.BeginInvoke(() =&gt;
  {
    richTextBox1.Xaml = "&lt;Paragraph&gt;Blah&lt;/Paragraph&gt;";
  });
  </code></pre>
  
  <p>However I get the following exception..</p>
  
  <pre><code>System.ArgumentException: value
     at System.Windows.Controls.RichTextBox.set_Xaml(String value)
  </code></pre>
  
  <p>Can anybody explain this ?<br>
  Maybe I am not in the </p>