title: Disabling button on Validation error
body: <p>I have couple of textboxes with custom validators:<br>
  (I don't mind if "wrong" data is sent back to object (the property is string), I just need to prevent the functionality of a button if there is an error, so if the binding is not the right place for that kind of validation please tell. I just like the Validation.ErrorTemplate support that i can use)</p>
  
  <pre><code>&lt;ControlTemplate x:Key="validator" &gt;
      &lt;DockPanel LastChildFill="True"&gt;
         &lt;TextBlock DockPanel.Dock="Right" Foreground="Red" FontSize="12pt"&gt;!&lt;/TextBlock&gt;
         &lt;Border BorderBrush="Red" BorderThickness="1.0"&gt;
              &lt;AdornedElementPlaceholder /&gt;
         &lt;/Border&gt;
      &lt;/DockPanel&gt;
  &lt;/ControlTemplate&gt;
  
  &lt;TextBox Height="23" Width="150"  TextWrapping="Wrap"
           Validation.ErrorTemplate="{StaticResource validator}"&gt;
           &lt;TextBox.Text&gt;
              &lt;Binding Path="StringProperty" UpdateSourceTrigger="LostFocus"&gt;
                 &lt;Binding.ValidationRules&gt;
                     &lt;local:NumbersOnly/&gt;
                 &lt;/Binding.ValidationRules&gt;
              &lt;/Binding&gt;
          &lt;/TextBox.Text&gt;
  &lt;/TextBox&gt;
  </code></pre>
  
  <p>How can I disable specific button if any of the validation error is raised? </p>
  
  <pre><code>&lt;Button Content="DO Work"  Height="57" HorizontalAlignment="Left"  Name="button1" VerticalAlignment="Top" Width="234" Click="button1_Click" /&gt;
  </code></pre>