.net如何根据年月算出这个月有几个星期五分别是哪几号,这个月的最后一天是星期几，是几号？

Question

如何根据年月算出：
1：算出这个月有几个星期五，分别是几号
2：算出这个月最后一天是星期几，是几号

Answer 1

DateTime   firstOfYear   =   DateTime.Parse("2008-05-31");    
int   firstOfWeek   =   Convert.ToInt32(firstOfYear.DayOfWeek);   
星期一的日期
private string getWeekMonday(System.DayOfWeek dw,string timeFormateStr)
  {
   int weeknow = Convert.ToInt32(dw);
   int moddayNum = (-1) * weeknow+1;
   string weekMonday = System.DateTime.Now.AddDays(moddayNum).Date.ToString(timeFormateStr);
   return weekMonday;
  }

Answer 2

Thread.CurrentThread.CurrentUICulture.Calendar
里面的方法很丰富了

Answer 3

发散
>>>>>>>>>>------------------------------------------------------------------------------------------<<<<<<<<<<

Answer 4

using System;
using System.Collections.Generic;namespace ConsoleApplication1
{
    internal class Program
    {
        private static void Main()
        {
            Console.WriteLine("1:算出这个月有几个星期五，分别是几号");
            foreach (DateTime time in GetFridays())
            {
                Console.WriteLine(time);
            }
            Console.WriteLine();
            Console.WriteLine("2：算出这个月最后一天是星期几，是几号");
            DateTime day = GetLastDay();
            Console.WriteLine(day.DayOfWeek);
            Console.WriteLine(day.Day);
            Console.ReadLine();
        }        //1：算出这个月有几个星期五，分别是几号 
        public static DateTime[] GetFridays()
        {
            List<DateTime> list = new List<DateTime>();
            DateTime day = new DateTime(DateTime.Now.Year, DateTime.Now.Month, 1);
            while (day.Month == DateTime.Now.Month)
            {
                if (day.DayOfWeek == DayOfWeek.Friday)
                {
                    list.Add(day);
                    day = day.AddDays(7);
                }
                else
                {
                    day = day.AddDays(1);
                }
            }
            return list.ToArray();
        }        //2：算出这个月最后一天是星期几，是几号 
        public static DateTime GetLastDay()
        {
            DateTime day = new DateTime(DateTime.Now.Year, DateTime.Now.Month + 1, 1);
            return day.AddDays(-1);
        }
    }
}