Java Date long to C# Datetime long

java date long -> C# datetime long:

 TimeSpan ts = TimeSpan.FromMilliseconds(javaNum);  
 DateTime dateTime = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Local);  
 DateTime dateTime2 = dateTime.Add(ts);  
 DateTime final = dateTime2.ToUniversalTime(); // Change to local-time  

C # -> java long

  private static DateTime Jan1st1970 = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);   
     
  public static long CurrentTimeMillis()   
  {   
     return (long) (DateTime.UtcNow - Jan1st1970).TotalMilliseconds;   
  }