title: Validation of Controlvalue with binding in Property Setter
body: <p>I have a normal TextBox in Silverlight and the text in bound to models property. In the Setter of the property I check for some rules. If the rules say that value is invalid then I do not set the new value (instead the old one will be left or an other one).</p>
  
  <p>Is there any way to inform the UI's TextBox that value changed. Because there is the only place in this Situation where the value is shown incorrect 
  (I tried ValidatesOnExceptions on BindingExpression and throw an exception in property, but nothing happened).</p>
  
  <p>I know that using IValidation-Interface's is a better way. But for my current archytecture the above Scenario seems to be better.</p>