title: Determining the Enter key is pressed in a TextBox
body: <p>Consider a XAML TextBox in Win Phone 7.</p>
  
  <pre><code>  &lt;TextBox x:Name="UserNumber"   /&gt;
  </code></pre>
  
  <p>The goal here is that when the user presses the <code>Enter</code> button on the on-screen keyboard, that would kick off some logic to refresh the content on the screen. </p>
  
  <p>I'd like to have an event raised specifically for <code>Enter</code>. Is this possible?</p>
  
  <ul>
  <li>Is the event specific to the TextBox, or is it a system keyboard event?</li>
  <li>Does it require a check for the <code>Enter</code> on each keypress? i.e. some analog to ASCII 13?</li>
  <li>What's the best way to code this requirement?</li>
  </ul>
  
  <p><img src="https://i.imgur.com/n2tbf.png" alt="alt text"></p>