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
通过这种方式计算,您可以选择一周中的哪一天表示新一周的开始(在示例中,我选择了星期一)。
请注意,对星期一进行这个计算将得到当前的星期一,而不是以前的星期一。
//Replace with whatever input date you want
DateTime inputDate = DateTime.Now;
//For this example, weeks start on Monday
int startOfWeek = (int)DayOfWeek.Monday;
//Calculate the number of days it has been since the start of the week
int daysSinceStartOfWeek = ((int)inputDate.DayOfWeek + 7 - startOfWeek) % 7;
DateTime previousStartOfWeek = inputDate.AddDays(-daysSinceStartOfWeek);
其他回答
让我们结合文化安全答案和扩展方法答案:
public static class DateTimeExtensions
{
public static DateTime StartOfWeek(this DateTime dt, DayOfWeek startOfWeek)
{
System.Globalization.CultureInfo ci = System.Threading.Thread.CurrentThread.CurrentCulture;
DayOfWeek fdow = ci.DateTimeFormat.FirstDayOfWeek;
return DateTime.Today.AddDays(-(DateTime.Today.DayOfWeek- fdow));
}
}
这将返回一周的开始和结束日期:
private string[] GetWeekRange(DateTime dateToCheck)
{
string[] result = new string[2];
TimeSpan duration = new TimeSpan(0, 0, 0, 0); //One day
DateTime dateRangeBegin = dateToCheck;
DateTime dateRangeEnd = DateTime.Today.Add(duration);
dateRangeBegin = dateToCheck.AddDays(-(int)dateToCheck.DayOfWeek);
dateRangeEnd = dateToCheck.AddDays(6 - (int)dateToCheck.DayOfWeek);
result[0] = dateRangeBegin.Date.ToString();
result[1] = dateRangeEnd.Date.ToString();
return result;
}
我已经在我的博客上发布了计算周、月、季度和年的开始/结束的完整代码 ZamirsBlog
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:(。
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;
}
这将是一周的第一个周日的午夜:
DateTime t = DateTime.Now;
t -= new TimeSpan ((int) t.DayOfWeek, t.Hour, t.Minute, t.Second);
这就给了你午夜的第一个星期一:
DateTime t = DateTime.Now;
t -= new TimeSpan ((int) t.DayOfWeek - 1, t.Hour, t.Minute, t.Second);