using System;

public class Program

{

    public static void Main()

    {

        DateTime d1 = new DateTime(1970, 1, 1);

        DateTime d2 = DateTime.Now;

        double x = new TimeSpan(d2.Ticks - d1.Ticks).TotalMilliseconds;

        double y =((DateTimeOffset)DateTime.UtcNow).ToUnixTimeMilliseconds();

        Console.WriteLine("Calculo com Ticks {0}",x);

        Console.WriteLine("Calculo com UtcNow {0}",y);

        Console.WriteLine("Data com millisegundos: {0:MM/dd/yyy HH:mm:ss.fff}, {1}", DateTime.Now,DateTime.Now.Millisecond);

    }

}

​

​