title: PasswordBox validation
body: <p>The Password property of the <code>PasswordBox</code> element is not a <code>DependencyObject</code> so cannot be bound (there is no Text property).  Capturing the password as the user types is possible by attaching a message to the <code>PasswordChanged</code> event, passing the source and grabbing it in the view model.  However the lack of binding means there no opportunity to set <code>ValidatesOnDataErrors=True</code> so the <code>IDataErrorInfo</code> methods are never call meaning any error template is never activated.  Anyone know how to resolve this? That is, is there another way to have an element invoke a call to the view model for the <code>IDataErrorInfo</code> indexer?</p>
  
  <p>One legitimate question might be why would you want to validate a password. </p>
  
  <p>Two reasons:  </p>
  
  <p>1) To let the user know the password is required.</p>
  
  <p>2) to let the user know if the password and password confirmation are the same.</p>