using System;

using System.Globalization;

class Donation

{ 

    public long Id; 

    public string LastIPAddress;

    public string Name;

    public string RawUrl;

}

​

public class Program

{

    const string start = "2019-01-18";

    const string end = "2019-01-19";

    public static void Main()

    {

        OldWay();

        Console.WriteLine("");

        NewWay();

    }

    public static void OldWay()

    {

        Console.WriteLine("Old way...");

​

        DateTime dt = new DateTime();

        dt = Convert.ToDateTime(start);

        string startUTC = dt.ToString("s");

​

        dt = Convert.ToDateTime(end);

        string endUTC = dt.ToString("s");

        Console.WriteLine("start in CST: " + start.ToString() + " || in UTC: " + startUTC);

        Console.WriteLine("end in CST: " + end.ToString() + " || in UTC: "  + endUTC);

    }

    public static void NewWay()

    {

        Console.WriteLine("New way...");

        var startDateTimeinCST = DateTime.Parse(start);

        var endDateTimeInCST = DateTime.Parse(end);

        Console.WriteLine("start in CST: " + startDateTimeinCST.ToString() + " || in UTC: " + ConvertToTimeZone(startDateTimeinCST, "UTC", "Central Standard Time"));

        Console.WriteLine("end in CST: " + endDateTimeInCST + " || in UTC: " + ConvertToTimeZone(endDateTimeInCST, "UTC", "Central Standard Time"));

    }

    public static DateTime ConvertToTimeZone(DateTime input, string toTZ, string fromTZ)

    {

        var timezoneinfoTo = TimeZoneInfo.FindSystemTimeZoneById(toTZ);

        var timezoneinfoFrom = TimeZoneInfo.FindSystemTimeZoneById(fromTZ);

​

        if(input.Kind == DateTimeKind.Local)

        {

            input = DateTime.SpecifyKind(input, DateTimeKind.Unspecified);

        }

​

        return TimeZoneInfo.ConvertTime(input, timezoneinfoFrom, timezoneinfoTo);

    }

}