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

    int BusinessDayDifference(DateTime Date1, DateTime Date2)
    {
        int Sign = 1;
        if (Date2 > Date1)
        {
            Sign = -1;
            DateTime TempDate = Date1;
            Date1 = Date2;
            Date2 = TempDate;
        }
        int BusDayDiff = (int)(Date1.Date - Date2.Date).TotalDays;
        if (Date1.DayOfWeek == DayOfWeek.Saturday)
            BusDayDiff -= 1;
        if (Date2.DayOfWeek == DayOfWeek.Sunday)
            BusDayDiff -= 1;
        int Week1 = GetWeekNum(Date1);
        int Week2 = GetWeekNum(Date2);
        int WeekDiff = Week1 - Week2;
        BusDayDiff -= WeekDiff * 2;
        foreach (DateTime Holiday in Holidays)
            if (Date1 >= Holiday && Date2 <= Holiday)
                BusDayDiff--;
        BusDayDiff *= Sign;
        return BusDayDiff;
    }

    private int GetWeekNum(DateTime Date)
    {
        return (int)(Date.AddDays(-(int)Date.DayOfWeek).Ticks / TimeSpan.TicksPerDay / 7);
    }