// C# Extension Method

// Doc: https://csharp-extension.com/en/method/1002226/datetime-isdaylightsavingtime

​

// @nuget: Z.ExtensionMethods

​

using System;

using System.Globalization;

​

public class Program

{

    public static void Main()

    {

        DateTime startDate = new DateTime(2018, 3, 11);

        DateTime endDate = new DateTime(2018, 11, 4);

        TimeSpan delta = startDate - endDate;

​

        DateTime date = new DateTime(2018, 8, 9);

        DaylightTime daylightTimes = new DaylightTime(startDate, endDate, delta);

​

        // C# Extension Method: DateTime  - IsDaylightSavingTime

        bool flag = date.IsDaylightSavingTime(daylightTimes);

​

        if (flag)

        {

            Console.WriteLine("{0} is a day light saving time.", date);

        }

    }

}