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
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));
其他回答
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);
在c#中试试这个。使用这段代码,您可以获得给定一周的第一个日期和最后一个日期。在这里,周日是第一天,周六是最后一天,但您可以根据您的文化设置这两天。
DateTime firstDate = GetFirstDateOfWeek(DateTime.Parse("05/09/2012").Date, DayOfWeek.Sunday);
DateTime lastDate = GetLastDateOfWeek(DateTime.Parse("05/09/2012").Date, DayOfWeek.Saturday);
public static DateTime GetFirstDateOfWeek(DateTime dayInWeek, DayOfWeek firstDay)
{
DateTime firstDayInWeek = dayInWeek.Date;
while (firstDayInWeek.DayOfWeek != firstDay)
firstDayInWeek = firstDayInWeek.AddDays(-1);
return firstDayInWeek;
}
public static DateTime GetLastDateOfWeek(DateTime dayInWeek, DayOfWeek firstDay)
{
DateTime lastDayInWeek = dayInWeek.Date;
while (lastDayInWeek.DayOfWeek != firstDay)
lastDayInWeek = lastDayInWeek.AddDays(1);
return lastDayInWeek;
}
using System;
using System.Globalization;
namespace MySpace
{
public static class DateTimeExtention
{
// ToDo: Need to provide culturaly neutral versions.
public static DateTime GetStartOfWeek(this DateTime dt)
{
DateTime ndt = dt.Subtract(TimeSpan.FromDays((int)dt.DayOfWeek));
return new DateTime(ndt.Year, ndt.Month, ndt.Day, 0, 0, 0, 0);
}
public static DateTime GetEndOfWeek(this DateTime dt)
{
DateTime ndt = dt.GetStartOfWeek().AddDays(6);
return new DateTime(ndt.Year, ndt.Month, ndt.Day, 23, 59, 59, 999);
}
public static DateTime GetStartOfWeek(this DateTime dt, int year, int week)
{
DateTime dayInWeek = new DateTime(year, 1, 1).AddDays((week - 1) * 7);
return dayInWeek.GetStartOfWeek();
}
public static DateTime GetEndOfWeek(this DateTime dt, int year, int week)
{
DateTime dayInWeek = new DateTime(year, 1, 1).AddDays((week - 1) * 7);
return dayInWeek.GetEndOfWeek();
}
}
}
namespace DateTimeExample
{
using System;
public static class DateTimeExtension
{
public static DateTime GetMonday(this DateTime time)
{
if (time.DayOfWeek != DayOfWeek.Monday)
return GetMonday(time.AddDays(-1)); //Recursive call
return time;
}
}
internal class Program
{
private static void Main()
{
Console.WriteLine(DateTime.Now.GetMonday());
Console.ReadLine();
}
}
}
你可以使用优秀的Umbrella库:
using nVentive.Umbrella.Extensions.Calendar;
DateTime beginning = DateTime.Now.BeginningOfWeek();
然而,它们似乎已经将星期一存储为一周的第一天(参见属性nvent . umbrelga . extensions . calendar . defaultdatetimecalendarexextensions . weekbeginson),因此先前的本地化解决方案要好一些。不幸的。
编辑:仔细看看这个问题,雨伞似乎也能解决这个问题:
// Or DateTime.Now.PreviousDay(DayOfWeek.Monday)
DateTime monday = DateTime.Now.PreviousMonday();
DateTime sunday = DateTime.Now.PreviousSunday();
尽管值得注意的是,如果你在周一要求前一个周一,它会给你7天。但如果你使用BeginningOfWeek,这也是正确的,这似乎是一个错误:(。