title: C#: Adding working days from a cetain date
body: <p>I have trouble doing this. I'm creating a method that add working days on a specific date.
  for example, I want to add 3 working days to sept 15, 2010 (Wednesday), the method would return sept 20 (Monday next week). it disregards saturday and sunday because its non-working day..</p>
  
  <p>Something like this in C#:</p>
  
  <pre><code>DateTime AddWorkingDays(DateTime specificDate, int workingDaysToAdd)
  {
     return specificDate + (workingDaysToAdd - (all saturdays and sundays))
  }
  </code></pre>
  
  <p>I don't consider special holidays on the computations, i just literally want to add days except saturday and sundays.. Thanks in advance! =)</p>