DateTime dt = DateTime.Now; //当前时间
DateTime startWeek = dt.AddDays(1 - Convert.ToInt32(dt.DayOfWeek.ToString("d"))); //本周周一
DateTime endWeek = startWeek.AddDays(6); //本周周日
DateTime startMonth = dt.AddDays(1 - dt.Day); //本月月初
DateTime endMonth = startMonth.AddMonths(1).AddDays(-1); //本月月末
DateTime startQuarter = dt.AddMonths(0 - (dt.Month - 1) % 3).AddDays(1 - dt.Day); //本季度初
DateTime endQuarter = startQuarter.AddMonths(3).AddDays(-1); //本季度末
DateTime startYear = new DateTime(dt.Year, 1, 1); //本年年初
DateTime endYear = new DateTime(dt.Year, 12, 31); //本年年末 //本周(要知道本周的第一天就得先知道今天是星期几,从而得知本周的第一天就是几天前的那一天,要注意的是这里的每一周是从周日始至周六止
string thisWeekStart = DateTime.Now.AddDays(Convert.ToDouble((0 - Convert.ToInt16(DateTime.Now.DayOfWeek)))).ToShortDateString(); string thisWeekEnd = DateTime.Now.AddDays(Convert.ToDouble((6 - Convert.ToInt16(DateTime.Now.DayOfWeek)))).ToShortDateString(); //上周,同理,一个周是7天,上周就是本周再减去7天,下周也是一样
string lastWeekStart = DateTime.Now.AddDays(Convert.ToDouble((0 - Convert.ToInt16(DateTime.Now.DayOfWeek))) - 7).ToShortDateString(); string lastWeekEnd = DateTime.Now.AddDays(Convert.ToDouble((6 - Convert.ToInt16(DateTime.Now.DayOfWeek))) - 7).ToShortDateString(); //下周
string nextWeekStart = DateTime.Now.AddDays(Convert.ToDouble((0 - Convert.ToInt16(DateTime.Now.DayOfWeek))) + 7).ToShortDateString(); string nextWeekEnd = DateTime.Now.AddDays(Convert.ToDouble((6 - Convert.ToInt16(DateTime.Now.DayOfWeek))) + 7).ToShortDateString(); //本月,本月的第一天嘛肯定是1号,最后一天就是下个月一号再减一天。
DateTime thisMonthStart = DateTime.Now.Year.ToString() + DateTime.Now.Month.ToString() + "1"; //第一天
DateTime thisMonthEnd = DateTime.Parse(DateTime.Now.Year.ToString() + DateTime.Now.Month.ToString() + "1").AddMonths(1).AddDays(-1).ToShortDateString();//最后一天 //巧用C#里ToString的字符格式化更简便
DateTime.Now.ToString("yyyy-MM-01"); DateTime.Parse(DateTime.Now.ToString("yyyy-MM-01")).AddMonths(1).AddDays(-1).ToShortDateString(); //上个月,减去一个月份
DateTime.Parse(DateTime.Now.ToString("yyyy-MM-01")).AddMonths(-1).ToShortDateString(); DateTime.Parse(DateTime.Now.ToString("yyyy-MM-01")).AddDays(-1).ToShortDateString(); //下个月,加去一个月份
DateTime.Parse(DateTime.Now.ToString("yyyy-MM-01")).AddMonths(1).ToShortDateString(); DateTime.Parse(DateTime.Now.ToString("yyyy-MM-01")).AddMonths(2).AddDays(-1).ToShortDateString(); //本年度,用ToString的字符格式化我们也很容易地算出本年度的第一天和最后一天
DateTime.Parse(DateTime.Now.ToString("yyyy-01-01")).ToShortDateString(); DateTime.Parse(DateTime.Now.ToString("yyyy-01-01")).AddYears(1).AddDays(-1).ToShortDateString(); //上年度,不用再解释了吧
DateTime.Parse(DateTime.Now.ToString("yyyy-01-01")).AddYears(-1).ToShortDateString(); DateTime.Parse(DateTime.Now.ToString("yyyy-01-01")).AddDays(-1).ToShortDateString(); //下年度
DateTime.Parse(DateTime.Now.ToString("yyyy-01-01")).AddYears(1).ToShortDateString(); DateTime.Parse(DateTime.Now.ToString("yyyy-01-01")).AddYears(2).AddDays(-1).ToShortDateString(); //本季度,很多人都会觉得这里难点,需要写个长长的过程来判断。其实不用的,我们都知道一年四个季度,一个季度三个月 //首先我们先把日期推到本季度第一个月,然后这个月的第一天就是本季度的第一天了
DateTime.Now.AddMonths(0 - ((DateTime.Now.Month - 1) % 3)).ToString("yyyy-MM-01"); //同理,本季度的最后一天就是下季度的第一天减一 DateTime.Parse(DateTime.Now.AddMonths(3 - ((DateTime.Now.Month - 1) % 3)).ToString("yyyy-MM-01")).AddDays(-1).ToShortDateString(); //下季度
DateTime.Now.AddMonths(3 - ((DateTime.Now.Month - 1) % 3)).ToString("yyyy-MM-01"); DateTime.Parse(DateTime.Now.AddMonths(6 - ((DateTime.Now.Month - 1) % 3)).ToString("yyyy-MM-01")).AddDays(-1).ToShortDateString(); //上季度
DateTime.Now.AddMonths(-3 - ((DateTime.Now.Month - 1) % 3)).ToString("yyyy-MM-01"); DateTime.Parse(DateTime.Now.AddMonths(0 - ((DateTime.Now.Month - 1) % 3)).ToString("yyyy-MM-01")).AddDays(-1).ToShortDateString();