C#日期判斷

日期：

/// <summary> 
        /// 判斷兩個日期是否在同一周 
        /// </summary> 
        /// <param name="dtmS">開始日期</param> 
        /// <param name="dtmE">結束日期</param>
        /// <returns></returns> 
        private bool IsInSameWeek(DateTime dtmS, DateTime dtmE)
        {
            TimeSpan ts = dtmE - dtmS;
            double dbl = ts.TotalDays;
            int intDow = Convert.ToInt32(dtmE.DayOfWeek);
            if (intDow == 0) intDow = 7;
            if (dbl >= 7 || dbl >= intDow) return false;
            else return true;
        }

        /// <summary>
        /// 某日期是本月的第幾周
        /// </summary>
        /// <param name="dtSel"></param>
        /// <param name="sundayStart"></param>
        /// <returns></returns>
        private int WeekOfMonth(DateTime dtSel, bool sundayStart)
        {
            //如果要判斷的日期為1號，則肯定是第一周了 
            if (dtSel.Day == 1) return 1;
            else
            {
                //得到本月第一天 
                DateTime dtStart = new DateTime(dtSel.Year, dtSel.Month, 1);
                //得到本月第一天是周幾 
                int dayofweek = (int)dtStart.DayOfWeek;
                //如果不是以周日開始，需要重新計算一下dayofweek，詳細風DayOfWeek枚舉的定義 
                if (!sundayStart)
                {
                    dayofweek = dayofweek - 1;
                    if (dayofweek < 0) dayofweek = 7;
                }
                //得到本月的第一周一共有幾天 
                int startWeekDays = 7 - dayofweek;
                //如果要判斷的日期在第一周范圍內，返回1 
                if (dtSel.Day <= startWeekDays) return 1;
                else
                {
                    int aday = dtSel.Day + 7 - startWeekDays;
                    return aday / 7 + (aday % 7 > 0 ? 1 : 0);
                }
            }
        }