using System;

public class Program

{

    public static void Main()

    {

        // This is the timezone that Norway is in. Check the documentation to find other countries.

        // https://docs.microsoft.com/en-us/windows-hardware/manufacture/desktop/default-time-zones

        // Norway   NO  W. Europe Standard Time (UTC+01:00) Amsterdam, Berlin, Bern, Rome, Stockholm, Vienna

        var norwegianTimeZone = TimeZoneInfo.FindSystemTimeZoneById("W. Europe Standard Time");

        // Here I specify a due date WITHOUT specifying the kind (i.e. local or UTC)

        var dueDate = new DateTime(2019, 3, 30, 0, 0, 0, 0, DateTimeKind.Unspecified);

        // Then I convert this to UTC specifying that the due date time zone is the Norwegian one

        var norwegianDueDate = TimeZoneInfo.ConvertTimeToUtc(dueDate, norwegianTimeZone);

        // Printing the original one outputs 2019-03-30T00:00:00.0000000

        Console.WriteLine(dueDate.ToString("O"));

        // Printing the UTC-adjusted one outputs 2019-03-29T23:00:00.0000000Z, which is the same as 2019-03-30T00:00:00.0000000+01:00

        Console.WriteLine(norwegianDueDate.ToString("O"));

​

    }

}