Start of week and end of week

DateTimeExtensions.cs

namespace Extensions
{
	public static class DateTimeExtensions
	{
		public static DateTime StartOfWeek(DateTime value)
		{
			var startOfWeek_ = DayOfWeek.Sunday;
			var delta = value.DayOfWeek - startOfWeek_;
			if (delta < 0)
				delta += 7;
			return value.AddDays(-delta).Date;
		}

		public static DateTime EndOfWeek(DateTime value)
		{
			var endOfWeek_ = DayOfWeek.Saturday;
			var delta = endOfWeek_ - value.DayOfWeek;
			if (delta < 0)
				delta += 7;
			return value.AddDays(delta).Date;
		}
	}
}