title: IDataErrorInfo : How to know if all properties are valid?
body: <p>I have a <code>WPF</code> application(<code>.Net 3.5</code>) which uses the <code>IDataErrorInfo</code> on the ViewModel to validate input.</p>
  
  <p>It works great, the usercontrol get the correct UI feedback.</p>
  
  <p>The problem is that the user can still change the selected element, or save this element.</p>
  
  <p>So my question is: How can I know that all my properties are valid? Or at least that all my displayed values are valid. The goal is to bind some <code>IsActive</code> on this result</p>