lblWeekStart.Content =
DateTime.Now.AddDays(Convert.ToDouble((0 -
Convert.ToInt16(DateTime.Now.DayOfWeek)))).ToShortDateString();
lblWeekEnd.Content = DateTime.Now.AddDays(Convert.ToDouble((6 -
Convert.ToInt16(DateTime.Now.DayOfWeek)))).ToShortDateString();
lblMouthStart.Content = DateTime.Today.AddDays(-(DateTime.Today.Day) +
1).ToString("yyyy-MM-dd");
lblMouthEnd.Content
=
DateTime.Today.AddMonths(1).AddDays(-(DateTime.Today.Day)).ToString("yyyy-MM-dd");//最后一天
lblQuarterStart.Content = DateTime.Today.AddMonths(0 - (DateTime.Today.Month -
1) % 3).AddDays(1 - DateTime.Today.Day).ToString("yyyy-MM-dd");
lblQuarterEnd.Content = DateTime.Today.AddMonths(0 - (DateTime.Today.Month - 1) % 3).AddDays(1 - DateTime.Today.Day).AddMonths(3).AddDays(-1).ToString("yyyy-MM-dd");
lblYearStart.Content = new DateTime(DateTime.Today.Year, 1, 1).ToString("yyyy-MM-dd");
lblYearEnd.Content = new DateTime(DateTime.Today.Year, 12, 31).ToString("yyyy-MM-dd");
说明：以lbl开头的为 Label 控件
WPF 本周、本月、本季、本年的第一天与最后一天取法,布布扣,bubuko.com
原文：http://www.cnblogs.com/kangjing/p/3718577.html