title: Checking for overlap between DateTime + TimeSpan
body: <p>I have <code>Appointment</code> objects made like this:</p>
  
  <pre><code>public Appointment(string p_Title, DateTime p_Start, TimeSpan p_Lenght)
  </code></pre>
  
  <p>I want to check if objects overlap but no matter what I try, I seem to get overlaps in every object that indicates the same day. I formated the DateTime to YYYY,MM,DD, HH:MM:SS. TimeSpan is HH:MM:SS</p>