UTC時間変換

ConvertUtc.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication6
{
    class Program
    {
        public static void Main()
        {
            TimeSpan ts = new TimeSpan(-1000);

            var timeZoneId = "Tokyo Standard Time";

            Console.WriteLine("{0} Time {1}", "UTC", ConvertTimeToUtc(new DateTime(2015, 7, 26, 11, 11, 12), timeZoneId));
            Console.WriteLine("{0} {1}", timeZoneId,
                ConvertTimeFromUtc(ConvertTimeToUtc(new DateTime(2015, 7, 26, 11, 11, 12), timeZoneId), timeZoneId));

            Console.ReadKey();
        }

        /// <summary>
        /// UTC時間から指定したタイムゾーンの時間に変換
        /// </summary>
        /// <param name="dateTime"></param>
        /// <param name="timeZoneId"></param>
        /// <returns></returns>
        private static DateTime ConvertTimeFromUtc(DateTime dateTime, string timeZoneId)
        {
            return ConvertTimeFromUtc(dateTime, TimeZoneInfo.FindSystemTimeZoneById(timeZoneId));
        }

        /// <summary>
        /// UTC時間から指定したタイムゾーンの時間に変換
        /// </summary>
        /// <param name="dateTime"></param>
        /// <param name="timeZoneInfo"></param>
        /// <returns></returns>
        private static DateTime ConvertTimeFromUtc(DateTime dateTime, TimeZoneInfo timeZoneInfo)
        {
            return TimeZoneInfo.ConvertTimeFromUtc(dateTime, timeZoneInfo);
        }

        /// <summary>
        /// UTC時間に変換
        /// </summary>
        /// <param name="dateTime"></param>
        /// <param name="timeZoneId"></param>
        /// <returns></returns>
        private static DateTime ConvertTimeToUtc(DateTime dateTime, string timeZoneId)
        {
            return ConvertTimeToUtc(dateTime, TimeZoneInfo.FindSystemTimeZoneById(timeZoneId));
        }

        /// <summary>
        /// UTC時間に変換
        /// </summary>
        /// <param name="dateTime"></param>
        /// <param name="timeZoneInfo"></param>
        /// <returns></returns>
        private static DateTime ConvertTimeToUtc(DateTime dateTime, TimeZoneInfo timeZoneInfo)
        {
            return TimeZoneInfo.ConvertTimeToUtc(dateTime, timeZoneInfo);
        }
    }
}