根据年月以及月中周次，获取该周开始，结束日期

注意，，是该月中的周次，一周最多有6周。

//获取周开始日期和结束日期（周日-周六）public string GetWeekDate(int yearly, int monthly, string weekly){string dayStr="";try{DateTime day1 = DateTime.Parse(yearly.ToString() + "-" + monthly.ToString() + "-01");//该月第一天日期int weekOfDay1 = (Int32)day1.DayOfWeek;//该月第一天是周几int dayCount = DateTime.DaysInMonth(yearly, monthly);//该月天数int endDay = 0;//结束日DateTime dateEnd = DateTime.Now;//周结束日期,初始化为当前时间//7*周次 – 第一周中上月天数 > 本月天数if (7 * Int32.Parse(weekly) – weekOfDay1 > dayCount){endDay = 7 * Int32.Parse(weekly) – weekOfDay1 – dayCount;DateTime dateLast = DateTime.Parse(yearly.ToString() + "-" + monthly.ToString() + "-" + dayCount.ToString());//该月最后一天日期dateEnd = dateLast.AddDays(endDay);}//7*周次 – 第一周中上月天数 > 本月天数if (7 * Int32.Parse(weekly) – weekOfDay1 <= dayCount){endDay = 7 * Int32.Parse(weekly) – weekOfDay1;dateEnd = DateTime.Parse(yearly.ToString() + "-" + monthly.ToString() + "-" + endDay.ToString());}DateTime dateStart = dateEnd.AddDays(-6); //周开始日期dayStr = dateStart.ToString("yyyy-MM-dd") +" ~ " + dateEnd.ToString("yyyy-MM-dd");}catch (Exception){throw;}return dayStr;}

调用：var resultWeekDay = GetWeekDate(2015, 4, 5);//4月第5周

结果：2015-04-26 ~ 2015-05-02

他们比任何人都分毫较量，又比任何人都口是心非。他们比任何人都依赖彼此，