Calculate the number of business days between two dates?

Question

In C#, how can I calculate the number of business (or weekdays) days between two dates?

Answer 1

Ok. I think it's time to post the right answer:

public static double GetBusinessDays(DateTime startD, DateTime endD)
{
    double calcBusinessDays =
        1 + ((endD - startD).TotalDays * 5 -
        (startD.DayOfWeek - endD.DayOfWeek) * 2) / 7;

    if (endD.DayOfWeek == DayOfWeek.Saturday) calcBusinessDays--;
    if (startD.DayOfWeek == DayOfWeek.Sunday) calcBusinessDays--;

    return calcBusinessDays;
}

Original Source:

http://alecpojidaev.wordpress.com/2009/10/29/work-days-calculation-with-c/

P.S. Solutions posted above making me sic for some reason.