title: format timestamp as string in c#
body: <p>I have a Timespan variable which should store the resulting subtraction operation from two datetime value and then display them in a dd:hh:mm format.</p>
  
  <p>This is what I have tried so far and it doesn't work</p>
  
  <pre><code>Duration=(DateTime.Now- instance.StagesInformations.Last().Value.TransactionDate).ToString("\\hh:mm")
  </code></pre>
  
  <p>Please help</p>