12

可能重复:
如何确定给定日期是否是该月的第 N 个工作日?

我如何获得每月的第 n 个工作日?

例如:

“2010 年 7 月”的第 2 个星期一 = 07/12/2010。

寻找类似的功能:

public DateTime GetNthWeekofMonth(DateTime date, int nthWeek, DayOfWeek dayofWeek)
{
//return the date of nth week of month
}

由上可知,函数的参数为​​("Any Date in July 2010", 2, Monday)。

4

4 回答 4

24

使用以下扩展方法:

public static class DateTimeExtensions
{
    ///<summary>Gets the first week day following a date.</summary>
    ///<param name="date">The date.</param>
    ///<param name="dayOfWeek">The day of week to return.</param>
    ///<returns>The first dayOfWeek day following date, or date if it is on dayOfWeek.</returns>
    public static DateTime Next(this DateTime date, DayOfWeek dayOfWeek) { 
        return date.AddDays((dayOfWeek < date.DayOfWeek ? 7 : 0) + dayOfWeek - date.DayOfWeek); 
    }
}

然后你可以写

new DateTime(2010, 07, 01).Next(DayOfWeek.Monday).AddDays((2 - 1) * 7);

或者,作为一个函数:

public DateTime GetNthWeekofMonth(DateTime date, int nthWeek, DayOfWeek dayOfWeek) {
    return date.Next(dayOfWeek).AddDays((nthWeek - 1) * 7);
}

(我需要减去一个,因为date.Next(dayOfWeek)那一天已经是第一次出现)

于 2010-07-19T19:51:26.370 回答
3

一种可能的算法:

  1. 从每月 1 日开始。
  2. 一天一天地向前推进,直到找到您正在寻找的星期几。
  3. 将 (7 * N) 添加到您所在的日期以获得您想要的日期。
于 2010-07-19T19:49:51.677 回答
0

可以在此处找到重复项:如何确定给定日期是否是该月的第 N 个工作日?

int d = date.Day; 
return date.DayOfWeek == dow && (d-1)/7 == (n-1); 
于 2010-07-19T19:49:58.977 回答
0
IEnumerable<DateTime> WeekdaysFrom( DateTime start )
{
    DateTime weekday = start.Add( TimeSpan.FromDays(1) );
    while( weekday < DateTime.MaxValue.Subtract( TimeSpan.FromDays(1) ) )
    {
        while( weekday.DayOfWeek == DayOfWeek.Saturday || weekday.DayOfWeek == DayOfWeek.Sunday )
        {
            weekday.Add( TimeSpan.FromDays(1) );
        }
        yield return weekday;
    }
}

DateTime NthWeekday( DateTime month, int n )
{
    return WeekdaysFrom( new DateTime( month.year, month.month, 1 ) ).Skip(n-1).First();
}
于 2010-07-19T19:57:27.730 回答