Convert DateTime In To Seconds Format And MilliSeconds Format And Vice Verse

The Conversion of DateTime format in to seconds is called Unix Timestamp

The Timestamp count starts from DateTime Of 1970-1-1 00:00:00, which is called Unix Epoch.

using System;

namespace UnixAndJavaTimeStampFormat

{

    class Program

    {

        static void Main(string[] args)

        {

            //Previous datetime based on Current datetime

            int limittime = 10;

            DateTime currentdatetime = DateTime.Now;

            DateTime beforeDateTime = currentdatetime.AddDays(-limittime);  // Substract days based on given limit, if minus(-) is given, otherwise it Adds no. of Days

            // DateTime beforeDateTime = currentdatetime.AddMinutes(-limittime);

            /// for seconds

            DateTime sTime = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);

            long unixTimestamp= (long)(beforeDateTime - sTime).TotalSeconds;

            Console.WriteLine("Unix Timestamp Format In Seconds : " + unixTimestamp);

            double timestamp = unixTimestamp;

            DateTime dateTimeformat = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);

            dateTimeformat = dateTimeformat.AddSeconds(timestamp);

            Console.WriteLine("Date Time Format For Seconds : "+ dateTimeformat);

            /// for milliseconds

            double unixTimestampmilliseconds = (long)(beforeDateTime - sTime).TotalMilliseconds;

            Console.WriteLine("Unix Timestamp Format In Milliseconds : " + unixTimestampmilliseconds);

            double milliTimestamp = unixTimestampmilliseconds;

            DateTime millidateTimeformat = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);

            millidateTimeformat = millidateTimeformat.AddMilliseconds(milliTimestamp);

            Console.WriteLine("Date Time Format for Milliseconds : " + millidateTimeformat);

            Console.ReadKey();

        }

    }

}