将毫秒转化成时分秒

        //将毫秒转换成时分秒
        public string formatLongToTimeStr(long a)
        {
            try
            {
                int hour = 0;
                int minute = 0;
                int second = 0;

                second = Convert.ToInt32(a) / 1000;

                if (second > 60)
                {
                    minute = second / 60;
                    second = second % 60;
                }
                if (minute > 60)
                {
                    hour = minute / 60;
                    minute = minute % 60;
                }
                var newHour = string.Empty;
                if (Convert.ToString(hour).Length < 2)
                {
                    newHour = "0" + Convert.ToString(hour);
                }
                else
                {
                    newHour = Convert.ToString(hour);
                }
                var newMinute = string.Empty;
                if (Convert.ToString(minute).Length < 2)
                {
                    newMinute = "0" + Convert.ToString(minute);
                }
                else
                {
                    newMinute = Convert.ToString(minute);
                }
                var newSecond = string.Empty;
                if (Convert.ToString(second).Length < 2)
                {
                    newSecond = "0" + Convert.ToString(second);
                }
                else
                {
                    newSecond = Convert.ToString(second);
                }
                return (newHour + ":" + newMinute + ":"
                        + newSecond);
            }
            catch (Exception)
            {
                return null;
            }
        }

求取2个时间的差值

   #region 获取时间差string GetTime(BsonString getTime)
        /// <summary>
        /// 获取时间差
        /// </summary>
        /// <param name="getTime">数据库时间</param>
        /// <returns>时间差</returns>
        private string GetTime(BsonString getTime)
        {
            var time1 = DateTime.ParseExact(Convert.ToString(getTime), "yyyy-MM-dd HH:mm:ss", null);
            var time = DateTime.Now - time1;

            if (time.TotalHours > 24)
            {
                return Math.Floor(time.TotalDays) + "天前";
            }
            if (time.TotalHours > 1)
            {
                return Math.Floor(time.TotalHours) + "小时前";
            }
            if (time.TotalMinutes > 1)
            {
                return Math.Floor(time.TotalMinutes) + "分钟前";
            }
            return Math.Floor(time.TotalSeconds) + "秒前";
        }
        #endregion