DateTime <-> UnixTime(long) 変換クラス

TimeUtils.cs

using System;

namespace MyApplication {
    
    public class TimeUtils {

        private static DateTime unixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, 0);

        private TimeUtils() {
        }

        /// <summary>
        /// Convert DateTime to the unix time[s].
        /// </summary>
        /// <returns>The unix time.</returns>
        /// <param name="t">DateTime.</param>
        public static long ToUnixTime(DateTime t) {
            return (long) (t - unixEpoch).TotalSeconds;
        }

        /// <summary>
        /// Convert the unix time[s] to DateTime.
        /// </summary>
        /// <returns>DateTime.</returns>
        /// <param name="unixTime">The unix time.</param>
        public static DateTime ToDateTime(long unixTime) {
            return unixEpoch.AddSeconds(unixTime);
        }
    }
}