C#获取每个年,月,周的起始日期和结束日期的方法

 /// 
 /// 声明期间类型枚举 /// 
 public enum Period {Day, Week, Month, Year}; /// 
 /// 获取指定期间的起止日期 /// 
 /// 期间类型 /// 开始日期 /// 结束日期 public static void GetPeriod(Period period, out DateTime beginDate, out DateTime endDate) { int year = DateTime.Today.Year; int month = DateTime.Today.Month; switch (period) { case Period.Year: //年 beginDate = new DateTime(year, 1, 1); endDate = new DateTime(year, 12, 31); break; case Period.Month: //月 beginDate = new DateTime(year, month, 1); endDate = beginDate.AddMonths(1).AddDays(-1); break; case Period.Week: //周 int week = (int)DateTime.Today.DayOfWeek; if (week == 0) week = 7; //周日 beginDate = DateTime.Today.AddDays(-(week - 1)); endDate = beginDate.AddDays(6); break; default: //日 beginDate = DateTime.Today; endDate = DateTime.Today; break; } }