C#获取每个年,月,周的起始日期和结束日期的方法

///

publicenumPeriod {Day, Week, Month, Year};

///

/// 期间类型

/// 开始日期

/// 结束日期

publicstaticvoidGetPeriod(Period period,outDateTime beginDate,outDateTime endDate)

{

  intyear = DateTime.Today.Year;

  intmonth = DateTime.Today.Month;

  switch(period)

  {

    casePeriod.Year://年

      beginDate =newDateTime(year, 1, 1);

      endDate =newDateTime(year, 12, 31);

      break;

    casePeriod.Month://月

      beginDate =newDateTime(year, month, 1);

      endDate = beginDate.AddMonths(1).AddDays(-1);

      break;

    casePeriod.Week://周

      intweek = (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;

  }

}