title: WPF TimeSpan binding to label without milliseconds
body: <p>In my current project i'm trying to show a label which has a TimeSpan binding.
  Actually the xaml looks simple:</p>
  
  <pre><code>&lt;Label Content="{Binding ElementName=Root, Path=DataSource.TimeTotal, StringFormat={}{0:hh\:mm}}"/&gt;
  </code></pre>
  
  <p>Which is exactly what is shown in <a href="https://stackoverflow.com/questions/5974763/binding-timespan-in-wpf-mvvm-and-show-only-minutesseconds">this question</a>. But it doesn't work, it shows always the full time and not only hours + minutes.</p>
  
  <p>I tested a lot of solutions but none of them worked.</p>