C#判断两个日期是否在同一周，某日期是本月的第几周

水深无声 2022-06-18 02:50 311阅读 0赞

/// <summary> 
            /// 判断两个日期是否在同一周 
            /// </summary> 
            /// <param name="dtmS">开始日期</param> 
            /// <param name="dtmE">结束日期</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>
            /// 某日期是本月的第几周
            /// </summary>
            /// <param name="dtSel"></param>
            /// <param name="sundayStart"></param>
            /// <returns></returns>
            private int WeekOfMonth(DateTime dtSel, bool sundayStart)
            {
                //如果要判断的日期为1号，则肯定是第一周了 
                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几 
                    int dayofweek = (int)dtStart.DayOfWeek;
                    //如果不是以周日开始，需要重新计算一下dayofweek，详细风DayOfWeek枚举的定义 
                    if (!sundayStart)
                    {
                        dayofweek = dayofweek - 1;
                        if (dayofweek < 0) dayofweek = 7;
                    }
                    //得到本月的第一周一共有几天 
                    int startWeekDays = 7 - dayofweek;
                    //如果要判断的日期在第一周范围内，返回1 
                    if (dtSel.Day <= startWeekDays) return 1;
                    else
                    {
                        int aday = dtSel.Day + 7 - startWeekDays;
                        return aday / 7 + (aday % 7 > 0 ? 1 : 0);
                    }
                }
            }