C#获取本周第一天和最后一天

            DateTime nowTime = DateTime.Now;
            #region 获取本周第一天
            //星期一为第一天
            int weeknow = Convert.ToInt32(nowTime.DayOfWeek);

            //因为是以星期一为第一天，所以要判断weeknow等于0时，要向前推6天。
            weeknow = (weeknow ==  ? ( - ) : (weeknow - ));
            int daydiff = (-) * weeknow;

            //本周第一天
            DateTime FirstDay = nowTime.AddDays(daydiff);
　　　　　　  #endregion

            #region 获取本周最后一天
            //星期天为最后一天
            int lastWeekDay = Convert.ToInt32(nowTime.DayOfWeek);
            lastWeekDay = lastWeekDay ==  ? ( - lastWeekDay) : lastWeekDay;
            int lastWeekDiff = ( - lastWeekDay);

            //本周最后一天
            DateTime LastDay = nowTime.AddDays(lastWeekDiff);

　　　　　　  #endregion