根据周几计算出月份总年中所有此日的日期值

/// <summary>
        /// 根据年月获取所有周几
        /// </summary>
        /// <param name="y">年</param>
        /// <param name="m">月份字符串</param>
        /// <param name="week">周几字符串(0:—....6:日)</param>
        /// <returns>时间列表</returns>
        public static List<string> GetAllWeek(int y, string m, string week)
        {
            List<string> dt = new List<string>();          // 用来记录每月周几存在列表

            string[] monthsArr = m.Substring(0, m.Length - 1).Split(‘,‘);  //获取每月
            foreach (string monthStr in monthsArr)
            {
                if (!string.IsNullOrEmpty(monthStr))
                {
                    int month = Convert.ToInt32(monthStr);
                    int Month_number = DateTime.DaysInMonth(y, month);          // 用来记录一个月中的天数     

                    for (int i = 1; i <= Month_number; i++)
                    {
                        string[] weektimeArr = week.Substring(0, week.Length - 1).Split(‘_‘);  //获取周几与时间
                        foreach (string wt in weektimeArr)
                        {
                            string w = wt.Split(‘、‘)[0];
                            if (!string.IsNullOrEmpty(w))
                            {
                                if (Common.Whether_Weekend(y, month, i, Convert.ToInt32(w)))
                                {
                                    dt.Add(w + "、" + month + "-" + i + "、" + wt.Split(‘、‘)[1]);
                                }
                            }
                        }
                    }
                }
            }
            return dt;
        }

        /// <summary>
        /// 根据年某月月获取所有周几
        /// </summary>
        /// <param name="y">年</param>
        /// <param name="m">月</param>
        /// <param name="week">周几(0:—....6:日)</param>
        /// <returns>时间列表</returns>
        public static List<DateTime> GetAllWeek(int y, int m, int week)
        {
            List<DateTime> dt = new List<DateTime>();          // 用来记录这月周几存在列表

            int Month_number = DateTime.DaysInMonth(y, m);     // 用来记录一个月中的天数     

            for (int i = 1; i <= Month_number; i++)
            {
                if (Common.Whether_Weekend(y, m, i, week))
                { dt.Add(Convert.ToDateTime(m + "-" + i)); }
            }
            return dt;
        }

        /// <summary>
        /// 计算是周几是否存在于某月
        /// </summary>
        /// <param name="y">年</param>
        /// <param name="m">月</param>
        /// <param name="d">天数</param>
        /// <param name="needdate">周几(0:—....6:日)</param>
        /// <returns>是否存在</returns>
        public static bool Whether_Weekend(int y, int m, int d, int needdate)
        {
            if (m == 1 || m == 2)
            {
                m += 12;
                y--;
            }
            int week = (d + 2 * m + 3 * (m + 1) / 5 + y + y / 4 - y / 100 + y / 400) % 7;   // 基姆拉尔森公式     
            if (week == needdate)
            {
                return true;
            }
            else
            {
                return false;
            }
        }