c# - 如何获得一周开始的 DateTime？

Question

如何在 C# 中仅知道当前时间来查找一周的开始时间(星期日和星期一)？

类似于:

DateTime.Now.StartWeek(Monday);

Answer 1

使用扩展方法:

public static class DateTimeExtensions
{
    public static DateTime StartOfWeek(this DateTime dt, DayOfWeek startOfWeek)
    {
        int diff = (7 + (dt.DayOfWeek - startOfWeek)) % 7;
        return dt.AddDays(-1 * diff).Date;
    }
}

可以按如下方式使用:

DateTime dt = DateTime.Now.StartOfWeek(DayOfWeek.Monday);
DateTime dt = DateTime.Now.StartOfWeek(DayOfWeek.Sunday);