title: WPF Binding One TextBox to two Properties
body: <p>Perhaps a simple question, but...
  So, I have bound a text box to a  property in ViewModel:</p>
  
  <pre><code>    &lt;TextBox x:Name="ololo"
   Text="{Binding VM.OloloText, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"&gt;
  </code></pre>
  
  <p>And there is a TextBlock near , that could change its Text property value due to some trigger logic that I have implemented beforehand:</p>
  
  <pre><code>&lt;Style TargetType="TextBlock"&gt;
       &lt;Style.Triggers&gt;
            &lt;DataTrigger Binding="{Binding ElementName=typeGallery, Path=SelectedValue}"
                Value="FirstType"&gt;
          &lt;Setter Property="Text" Value="AAA" /&gt;
            &lt;/DataTrigger&gt;
             &lt;DataTrigger Binding="{Binding ElementName=typeGallery, Path=SelectedValue}"
                  Value="Second Type"&gt;
              &lt;Setter Property="Text" Value="BBB" /&gt;
             &lt;/DataTrigger&gt; 
                                         ...
  </code></pre>
  
  <p>So, this TextBlock has values <code>AAA</code> or <code>BBB</code> . All this is working like a charm.
  The question is how to bind the ololo TextBox to one property, say <code>VM.OloloText</code> if there is <code>AAA</code> value in TextBlock and to other property (<code>VM.ololoText2</code>)  if TextBlock value is <code>BBB</code> ?</p>