我如何在c#中找到一周的开始(包括周日和周一),只知道当前时间?
喜欢的东西:
DateTime.Now.StartWeek(Monday);
我如何在c#中找到一周的开始(包括周日和周一),只知道当前时间?
喜欢的东西:
DateTime.Now.StartWeek(Monday);
当前回答
c#中的模数对-1 mod 7(它应该是6,但c#返回-1)效果很差 所以…一个“一行程序”的解决方案是这样的:
private static DateTime GetFirstDayOfWeek(DateTime date)
{
return date.AddDays(
-(((int)date.DayOfWeek - 1) -
(int)Math.Floor((double)((int)date.DayOfWeek - 1) / 7) * 7));
}
其他回答
我尝试了几次,但我没有解决从星期一开始的一周的问题,导致我的下一个星期一是星期天。所以我对它做了一些修改,让它与下面的代码一起工作:
int delta = DayOfWeek.Monday - DateTime.Now.DayOfWeek;
DateTime monday = DateTime.Now.AddDays(delta == 1 ? -6 : delta);
return monday;
这将给你前一个星期天(我想):
DateTime t = DateTime.Now;
t -= new TimeSpan ((int) t.DayOfWeek, 0, 0, 0);
步骤1:
创建静态类
public static class TIMEE
{
public static DateTime StartOfWeek(this DateTime dt, DayOfWeek startOfWeek)
{
int diff = (7 + (dt.DayOfWeek - startOfWeek)) % 7;
return dt.AddDays(-1 * diff).Date;
}
public static DateTime EndOfWeek(this DateTime dt, DayOfWeek startOfWeek)
{
int diff = (7 - (dt.DayOfWeek - startOfWeek)) % 7;
return dt.AddDays(1 * diff).Date;
}
}
第二步:使用这个类来确定一周的开始和结束日期
DateTime dt = TIMEE.StartOfWeek(DateTime.Now ,DayOfWeek.Monday);
DateTime dt1 = TIMEE.EndOfWeek(DateTime.Now, DayOfWeek.Sunday);
稍微啰嗦一点,了解一下文化:
System.Globalization.CultureInfo ci =
System.Threading.Thread.CurrentThread.CurrentCulture;
DayOfWeek fdow = ci.DateTimeFormat.FirstDayOfWeek;
DayOfWeek today = DateTime.Now.DayOfWeek;
DateTime sow = DateTime.Now.AddDays(-(today - fdow)).Date;
我们喜欢简单的语句:获取当前文化中每周的第一天与当前日期之间的差值,然后从当前日期减去天数:
var weekStartDate = DateTime.Now.AddDays(-((int)now.DayOfWeek - (int)DateTimeFormatInfo.CurrentInfo.FirstDayOfWeek));