C# ローカルシステム時刻を設定直し

    /// <summary>
    ///システム時間クラス
    /// </summary>
    [StructLayout(LayoutKind.Sequential)]
    public class SystemTime
    {
        public ushort year;//年
        public ushort month;//月
        public ushort dayofweek;//曜日
        public ushort day;//日
        public ushort hour;//時
        public ushort minute;//分
        public ushort second;//秒
    }

    /// <summary>
    /// Windows API
    /// </summary>
    public class WinAPI
    {
        [DllImport("Kernel32.dll")]
        private static extern Boolean SetLocalTime([In, Out] SystemTime st);

        /// <summary>
        /// システム時刻をセット
        /// </summary>
        /// <param name="newdatetime">新しい時刻</param>
        /// <returns></returns>
        public static bool SetLocalTime(DateTime newdatetime)
        {
            SystemTime st = new SystemTime();
            st.year = Convert.ToUInt16(newdatetime.Year);//年
            st.month = Convert.ToUInt16(newdatetime.Month);//月
            st.day = Convert.ToUInt16(newdatetime.Day);//日
            st.hour = Convert.ToUInt16(newdatetime.Hour);//時
            st.minute = Convert.ToUInt16(newdatetime.Minute);//分
            st.second = Convert.ToUInt16(newdatetime.Second);//秒
            return SetLocalTime(st);
        }
    }