Check if daylight savings is in effect?

Question

How to check if in Denmark daylight time savings has taken effect, if so, then add 1 hour to my data, else not? I have a xml file:

Answer 1

Based on other codes provided above, I made a complete code to run and make tests. The variable cityTz is receiving an IANA timezone name example. IANA timezone pattern is used in Mac and Linux (Windows uses different timezone style). In 2020, daylight-saving (DST) in New York ends on November 01. If you test the code below, the return will be FALSE, because "theDate" is November 02, the next day after the end of DST. But if you change the line commented and set theDate to November 01 (last DST date in NY), the return will be TRUE.

You can compile this program in Mac or Linux terminal typing:

csc testDST.cs

To run your program:

mono testDST.exe

Complete code:

using System;
using System.Collections.Generic;
using System.Linq;

class Program{
    static void Main(string[] args)
    {
        string cityTz;

        //cityTz = "America/Sao_Paulo";
        cityTz = "America/New_York";

        //DateTime theDate = new DateTime(2020, 11, 1); //returns TRUE
        DateTime theDate = new DateTime(2020, 11, 2); //returns FALSE

        Console.WriteLine("Data: "+theDate);

        TimeZoneInfo tzi = TimeZoneInfo.FindSystemTimeZoneById(cityTz);
        bool isDaylight = tzi.IsDaylightSavingTime(theDate);

        Console.WriteLine("isDaylight this date in "+ cityTz +"?: "+ isDaylight);
    }
}