title: c# Determine how many hours in a time period fall within specific hours
body: <p>I have a time period of an incident (e.g. 06 April 2014 at 11:30 until 08 April 2014 at 10:15) and I have office opening hours (e.g. 9:00 to 17:00 Monday to Friday).</p>
  
  <p>I need to calculate the number of opening hours (as a decimal) that were affected by the incident.</p>
  
  <p>I can think of a way I can do this but it seems very lengthy and messy so wanted to see if anyone could come up with something elegant?</p>
  
  <p>Thanks
  Kev</p>