using System;

public class Program

{

    public static void Main()

    {

        double timestamp = 1519551404;

​

// Format our new DateTime object to start at the UNIX Epoch

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

​

// Add the timestamp (number of seconds since the Epoch) to be converted

dateTime = dateTime.AddSeconds(timestamp);

        var dateTime2 = new DateTime(2015, 05, 24, 10, 2, 0, DateTimeKind.Local);

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

var unixDateTime = (dateTime2.ToUniversalTime() - epoch).TotalSeconds;

        Console.WriteLine(dateTime+"\n" + dateTime2);

        DateTimeOffset dto = new DateTimeOffset(1970, 1, 1, 0, 0, 0, TimeSpan.Zero);

      Console.WriteLine("{0} --> Unix Seconds: {1}", dto, dto.ToUnixTimeSeconds());

​

      dto = new DateTimeOffset(2018, 12, 31, 23, 59, 0, TimeSpan.Zero);

      Console.WriteLine("{0} --> Unix Seconds: {1}", dto, dto.ToUnixTimeSeconds());

​

      dto = new DateTimeOffset(1970, 1, 1, 0, 1, 0, TimeSpan.Zero);

      Console.WriteLine("{0} --> Unix Seconds: {1}", dto, dto.ToUnixTimeSeconds());

   }

    }

​