C# 秒数转日期_由秒数得到日期几天几小时_当前日期时间,转换为秒

       ///<summary>
        ///由秒数得到日期几天几小时。。。
        ///</summary
        ///<param name="t">秒数</param>
        ///<param name="type">0：转换后带秒，1:转换后不带秒</param>
        ///<returns>几天几小时几分几秒</returns>
        public static string parseTimeSeconds(int t, int type)
        {
            string r = "";
            int day, hour, minute, second;

            if (t >= 86400)  //天,
            {
                day = Convert.ToInt16(t / 86400);
                hour = Convert.ToInt16((t % 86400) / 3600);
                minute = Convert.ToInt16((t % 86400 % 3600) / 60);
                second = Convert.ToInt16(t % 86400 % 3600 % 60);
                if (type == 0)
                    r = day + ("day") + hour + ("hour") + minute + ("minute") + second + ("second");
                else
                    r = day + ("day") + hour + ("hour") + minute + ("minute");

            }
            else if (t >= 3600)//时,
            {
                hour = Convert.ToInt16(t / 3600);
                minute = Convert.ToInt16((t % 3600) / 60);
                second = Convert.ToInt16(t % 3600 % 60);
                if (type == 0)
                    r = hour + ("hour") + minute + ("minute") + second + ("second");
                else
                    r = hour + ("hour") + minute + ("minute");
            }
            else if (t >= 60)//分
            {
                minute = Convert.ToInt16(t / 60);
                second = Convert.ToInt16(t % 60);
                r = minute + ("minute") + second + ("second");
            }
            else
            {
                second = Convert.ToInt16(t);
                r = second + ("second");
            }
            return r;
        }

        /// <summary>
        /// 当前日期时间，转换为秒
        /// </summary>
        /// <returns>秒数</returns>
        public static string xDateSeconds()
        {
            long xdateseconds = 0;
            DateTime xdatenow = DateTime.UtcNow;     //当前UTC时间

            long xminute = 60;      //一分种60秒
            long xhour = 3600;
            long xday = 86400;
            long byear = 1970;//从1970-1-1 0：00：00开始到现在所过的秒
            long[] xmonth = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
            long[] xyear = { 365, 366 };
            long num = 0;

            xdateseconds += xdatenow.Second;    //算秒
            xdateseconds += xdatenow.Minute * xminute;      //算分
            xdateseconds += xdatenow.Hour * xhour;      //算时
            xdateseconds += (xdatenow.Day - 1) * xday;        //算天

            //算月(月换成天算)
            if (DateTime.IsLeapYear(xdatenow.Year))
            {
                xdateseconds += (xmonth[xdatenow.Month - 1] + 1) * xday;
            }
            else
            {
                xdateseconds += (xmonth[xdatenow.Month - 1]) * xday;
            }

            //算年（年换成天算）
            long lyear = xdatenow.Year - byear;

            for (int i = 0; i < lyear; i++)
            {
                if (DateTime.IsLeapYear((int)byear + i))
                {
                    num++;
                }
            }

            xdateseconds += ((lyear - num) * xyear[0] + num * xyear[1]) * xday;

            return xdateseconds.ToString();
        }

        /// <summary>
        /// 秒数转日期
        /// </summary>
        /// <param name="Value">秒数</param>
        /// <returns>日期</returns>
        public static DateTime GetGMTDateTime(int Value)
        {
            //秒数转时间日期
            //GMT时间从2000年1月1日开始，先把它作为赋为初值
            long Year = 2000, Month = 1, Day = 1;
            long Hour = 0, Min = 0, Sec = 0;
            //临时变量
            long iYear = 0, iDay = 0;
            long iHour = 0, iMin = 0, iSec = 0;
            //计算文件创建的年份
            iYear = Value / (365 * 24 * 60 * 60);
            Year = Year + iYear;
            //计算文件除创建整年份以外还有多少天
            iDay = (Value % (365 * 24 * 60 * 60)) / (24 * 60 * 60);
            //把闰年的年份数计算出来
            int RInt = 0;
            for (int i = 2000; i < Year; i++)
            {
                if ((i % 4) == 0)
                    RInt = RInt + 1;
            }
            //计算文件创建的时间(几时)
            iHour = ((Value % (365 * 24 * 60 * 60)) % (24 * 60 * 60)) / (60 * 60);
            Hour = Hour + iHour;
            //计算文件创建的时间(几分)
            iMin = (((Value % (365 * 24 * 60 * 60)) % (24 * 60 * 60)) % (60 * 60)) / 60;
            Min = Min + iMin;
            //计算文件创建的时间(几秒)
            iSec = (((Value % (365 * 24 * 60 * 60)) % (24 * 60 * 60)) % (60 * 60)) % 60;
            Sec = Sec + iSec;
            DateTime t = new DateTime((int)Year, (int)Month, (int)Day, (int)Hour, (int)Min, (int)Sec);
            DateTime t1 = t.AddDays(iDay - RInt);
            return t1;
        }

把总秒数转换成DataTime格式，注意时区，默认是格林威治时间GMT

DateTime dt = new DateTime(1970, 1, 1, 0, 0, 0, 0).ToLocalTime().AddSeconds(info.lTime);
                        uploadtime.Text = string.Format("{0:F}", dt);