public static void Main()
TimeSpan t = DateTime.Parse("2015/4/19 9:16:40 AM") - new DateTime(1970, 1, 1);
int secondsSinceEpoch = (int)t.TotalSeconds;
Console.WriteLine( secondsSinceEpoch);
Console.WriteLine(new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc).AddSeconds( secondsSinceEpoch) );