title: Changing format xxxxxxxxxx to xxx-xxx-xxxx
body: <p>I have a textbox in WPF and I need to display text in <strong>xxx-xxx-xxxx</strong> format.</p>
  
  <pre><code>&lt;TextBox FontSize="30" Text="{Binding MyString,UpdateSourceTrigger=PropertyChanged}" Grid.Row="3" MaxLength="10"&gt;&lt;/TextBox&gt;
  </code></pre>
  
  <p><code>MyString</code> is just property which sets value in TextBox into it for some other logic. Can I do it in XAML itself usng StringFormat?</p>