C#里巧用DateTime预设一些可选的日期范围(如本年度、本季度、本月等)

                //大家在做报表或查询的时候都会有给用户预设一些可选的日期范围(如上图)
                
//如本年度销售额、本季度利润、本月新增客户
                
//C#里内置的DateTime基本上都可以实现这些功能,巧用DateTime会使你处理这些事来变轻松多了
               
                
//今天
                DateTime.Now.Date.ToShortDateString();
                
//昨天,就是今天的日期减一
                DateTime.Now.AddDays(-1).ToShortDateString();
                
//明天,同理,加一
                DateTime.Now.AddDays(1).ToShortDateString();

                
//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
                DateTime.Now.AddDays(Convert.ToDouble((0 - Convert.ToInt16(DateTime.Now.DayOfWeek)))).ToShortDateString();
                DateTime.Now.AddDays(Convert.ToDouble((
6 - Convert.ToInt16(DateTime.Now.DayOfWeek)))).ToShortDateString();
                
//如果你还不明白,再看一下中文显示星期几的方法就应该懂了
                
//由于DayOfWeek返回的是数字的星期几,我们要把它转换成汉字方便我们阅读,有些人可能会用switch来一个一个地对照,其实不用那么麻烦的              
                string[] Day = new string[] "星期日""星期一""星期二""星期三""星期四""星期五""星期六" };
                Day[Convert.ToInt16(DateTime.Now.DayOfWeek)];

                
//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
                DateTime.Now.AddDays(Convert.ToDouble((0 - Convert.ToInt16(DateTime.Now.DayOfWeek))) - 7).ToShortDateString();
                DateTime.Now.AddDays(Convert.ToDouble((
6 - Convert.ToInt16(DateTime.Now.DayOfWeek))) - 7).ToShortDateString();
                
//下周
                DateTime.Now.AddDays(Convert.ToDouble((0 - Convert.ToInt16(DateTime.Now.DayOfWeek))) + 7).ToShortDateString();
                DateTime.Now.AddDays(Convert.ToDouble((
6 - Convert.ToInt16(DateTime.Now.DayOfWeek))) + 7).ToShortDateString();
                
//本月,很多人都会说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。当然这是对的
                
//一般的写法
                DateTime.Now.Year.ToString() + DateTime.Now.Month.ToString() + "1"//第一天
                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();
                
//7天后
                DateTime.Now.Date.ToShortDateString();
                DateTime.Now.AddDays(
7).ToShortDateString();
                
//7天前
                DateTime.Now.AddDays(-7).ToShortDateString();
                DateTime.Now.Date.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,相信你们都知道了。。。。收工
                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();

posted @ 2006-10-20 09:59 李振波 阅读(...) 评论(...) 编辑 收藏