Caclulate Weekdays between two dates

A way to calculate how many weekdays are there between two dates.

public static int GetWeekDays(DateTime startDate, DateTime endDate)
{
    startDate = startDate.Date;
    endDate = endDate.Date;

    if (endDate <= startDate)
        return 0;

    TimeSpan ts = endDate - startDate;
    int wholeWeeks = ts.Days / 7;
    int result = wholeWeeks * 5;

    DateTime fractionalStartDate = startDate.AddDays(wholeWeeks * 7);
    int loop = ts.Days % 7;
    while (loop > 0)
    {
        if (((int)fractionalStartDate.DayOfWeek) % 6 > 0)
            result++;

        fractionalStartDate = fractionalStartDate.AddDays(1);
        loop--;
    }

    return result;
}