计算C#中两个日期之间的工作日数

Question

我怎样才能获得两个给定日期之间的工作日数量,而不只是迭代工作日之间的日期和计算工作日？

似乎相当简单,但我似乎找不到符合以下条件的确凿正确答案:

1. 总数应该是包含的,因此GetNumberOfWeekdays(new DateTime(2009,11,30),new DateTime(2009,12,4))应该等于5,即周一到周五.
2. 应该允许闰日
3. 不只是在计算工作日期间迭代所有日期.

我发现了一个类似的问题,答案很接近,但不正确

Answer 1

O(1)解决方案:

// Count days from d0 to d1 inclusive, excluding weekends
public static int countWeekDays(DateTime d0, DateTime d1)
{
    int ndays = 1 + Convert.ToInt32((d1 - d0).TotalDays);
    int nsaturdays = (ndays + Convert.ToInt32(d0.DayOfWeek)) / 7;
    return ndays - 2 * nsaturdays
           - (d0.DayOfWeek == DayOfWeek.Sunday ? 1 : 0)
           + (d1.DayOfWeek == DayOfWeek.Saturday ? 1 : 0);
}

2014年1月的例子:

    January 2014
Su Mo Tu We Th Fr Sa
          1  2  3  4
 5  6  7  8  9 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25
26 27 28 29 30 31

countWeekDays(new DateTime(2014, 1, 1), new DateTime(2014, 1, 1)); // 1
countWeekDays(new DateTime(2014, 1, 1), new DateTime(2014, 1, 2)); // 2
countWeekDays(new DateTime(2014, 1, 1), new DateTime(2014, 1, 3)); // 3
countWeekDays(new DateTime(2014, 1, 1), new DateTime(2014, 1, 4)); // 3
countWeekDays(new DateTime(2014, 1, 1), new DateTime(2014, 1, 5)); // 3
countWeekDays(new DateTime(2014, 1, 1), new DateTime(2014, 1, 6)); // 4

注意DateTime输入应该在一天的大致同一时间.如果您DateTime仅根据上面的示例创建基于年,月和日的对象,那么您应该没问题.作为一个反例,1月1日上午12点01分到1月2日晚上11:59仅跨越2天,但如果你使用这些时间,上述功能将计为3.

Answer 2

从这个链接:

    public static int Weekdays(DateTime dtmStart, DateTime dtmEnd)
    {
        // This function includes the start and end date in the count if they fall on a weekday
        int dowStart = ((int)dtmStart.DayOfWeek == 0 ? 7 : (int)dtmStart.DayOfWeek);
        int dowEnd = ((int)dtmEnd.DayOfWeek == 0 ? 7 : (int)dtmEnd.DayOfWeek);
        TimeSpan tSpan = dtmEnd - dtmStart;
        if (dowStart <= dowEnd)
        {
            return (((tSpan.Days / 7) * 5) + Math.Max((Math.Min((dowEnd + 1), 6) - dowStart), 0));
        }
        return (((tSpan.Days / 7) * 5) + Math.Min((dowEnd + 6) - Math.Min(dowStart, 6), 5));
    }


  [1]: http://www.eggheadcafe.com/community/aspnet/2/44982/how-to-calculate-num-of-w.aspx

测试(每个测试返回5):

    int ndays = Weekdays(new DateTime(2009, 11, 30), new DateTime(2009, 12, 4));
    System.Console.WriteLine(ndays);

    // leap year test
    ndays = Weekdays(new DateTime(2000, 2,27), new DateTime(2000, 3, 5));
    System.Console.WriteLine(ndays);

    // non leap year test
    ndays = Weekdays(new DateTime(2007, 2, 25), new DateTime(2007, 3, 4));
    System.Console.WriteLine(ndays);