C#获取当月的第一天最后一天 获取本周第一天最后一天 

 1 　　　　　　　DateTime nowTime = DateTime.Now;
 2             #region 获取本周第一天
 3             //星期一为第一天  
 4             int weeknow = Convert.ToInt32(nowTime.DayOfWeek);
 5 
 6             //因为是以星期一为第一天，所以要判断weeknow等于0时，要向前推6天。  
 7             weeknow = (weeknow == 0 ? (7 - 1) : (weeknow - 1));
 8             int daydiff = (-1) * weeknow;
 9 
10             //本周第一天  
11             DateTime FirstDay = nowTime.AddDays(daydiff);
12             #endregion
13 
14             #region 获取本周最后一天
15             //星期天为最后一天  
16             int lastWeekDay = Convert.ToInt32(nowTime.DayOfWeek);
17             lastWeekDay = lastWeekDay == 0 ? (7 - lastWeekDay) : lastWeekDay;
18             int lastWeekDiff = (7 - lastWeekDay);
19 
20             //本周最后一天  
21             DateTime LastDay = nowTime.AddDays(lastWeekDiff);
22             #endregion
23 
24             //获取当前月的第一天
25             DateTime d1 = new DateTime(nowTime.Year, nowTime.Month, 1);
26 
27             //获取当前月的最后一天
28             DateTime d2 = d1.AddMonths(1).AddDays(-1);
29 
30             Console.WriteLine(FirstDay);
31             Console.WriteLine(LastDay);
32             Console.WriteLine(d1);
33             Console.WriteLine(d2);
34             Console.Read();

 

posted @ 2020-12-22 09:18  .NET____小白  阅读(669)  评论(0)    收藏  举报