title: Wpf Binding + DataTrigger
body: <p>Hello I have a problem with Binding and DataTrigger. So my code is:</p>
  
  <pre><code>&lt;tog:HorizontalToggleSwitch  Margin="0,10,15,0" HorizontalAlignment="Left"  &gt;
  &lt;tog:HorizontalToggleSwitch.Style&gt;
    &lt;Style TargetType="{x:Type tog:HorizontalToggleSwitch}"&gt;
    &lt;Setter Property="IsChecked" Value="{Binding Staff.isSelfie, Mode=TwoWay}"/&gt;
       &lt;Style.Triggers&gt;
        &lt;DataTrigger Binding="{Binding ElementName=Admin,Path=IsChecked}" Value="True"&gt;
          &lt;Setter Property="IsChecked" Value="True" /&gt;
          &lt;Setter Property="IsEnabled" Value="False"/&gt;
        &lt;/DataTrigger&gt;
       &lt;DataTrigger Binding="{Binding ElementName=Admin,Path=IsChecked}" Value="False"&gt;
         &lt;Setter Property="IsChecked" Value="False" /&gt;
         &lt;Setter Property="IsEnabled" Value="True"/&gt;
       &lt;/DataTrigger&gt;
      &lt;/Style.Triggers&gt;
      &lt;/Style&gt;
   &lt;/tog:HorizontalToggleSwitch.Style&gt;
   &lt;/tog:HorizontalToggleSwitch&gt;
  </code></pre>
  
  <p>As you can see I have a  binding value <code>Staff.isSelfie</code> at IsChecked Property and I change it within the Datatrigger. My problem is that I don't get the bool value of IsChecked at my variable <code>Staff.isSelfie</code>.  DataTrigger works because the switch change from off to on while I click at Admin Element which is a radiobutton. The code from <code>Staff.isSelfie</code> is:</p>
  
  <pre><code>bool _isSelfie;
      [DataMember]
      public bool isSelfie
      {
          get
          {
              return _isSelfie;
          }
  
          set
          {
              if (_isSelfie != value)
              {
                  _isSelfie = value;
                  OnPropertyChanged(nameof(isSelfie));
              }
          }
      }
  </code></pre>
  
  <p>which implement INotifyPropertyChanged. The variable <code>Staff.isSelfie</code> take his value from a bool in my database thats why I want to set it at the begin. How can I get the value true or false from DataTrigger to my variable <code>Staff.isSelfie</code>? What is wrong? Thanks a lot.</p>