title: how to edit a WPF textbox which uses multibinding and string.format?
body: <p>I have the following code.</p>
  
  <p>This displays data in following format H:M:S. I would like to edit these values...and wanted to be notified in viewmodel.</p>
  
  <p>How do I achieve that ?</p>
  
  <p>Any help would be appreciated. Thanks</p>
  
  <pre><code>  &lt;TextBox  DataContext="{Binding UpdateSourceTrigger=PropertyChanged}" &gt;
                              &lt;TextBox.Text&gt;
                                  &lt;MultiBinding StringFormat=" {0}:{1}:{2}"&gt;
                                  &lt;Binding Path="ValueH" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged" /&gt;
                                  &lt;Binding Path="ValueM" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged"  /&gt;
                                  &lt;Binding Path="ValueS" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged"  /&gt;
                              &lt;/MultiBinding&gt;
                          &lt;/TextBox.Text&gt;
                          &lt;/TextBox&gt;
  </code></pre>