UnixTime (edit)

DateTimeOffset.ToUnixTimeMilliseconds Method (System) | Microsoft Docs

How to get the unix timestamp in C# - Stack Overflow

How To Convert DateTime To UnixTimeStamp in C# (tutorialsrack.com)

using System;
 
namespace ConsoleApp1
{
    public static class DateTimeHelper
    {
        public static long GetUnixTimeMilliseconds()
        {
            return DateTime.UtcNow.ToUnixTimeMilliseconds();
        }
 
        public static long GetUnixTimeSeconds()
        {
            return DateTime.UtcNow.ToUnixTimeSeconds();
        }
 
        public static long ConvertToUnixTimeMilliseconds()
        {
            return DateTime.UtcNow.ConvertToUnixTimeMilliseconds();
        }
 
        public static long ConvertToUnixTimeSeconds()
        {
            return DateTime.UtcNow.ConvertToUnixTimeSeconds();
        }
 
        /// <summary>
        /// Using DateTimeOffset
        /// </summary>
        /// <param name="date"></param>
        /// <returns></returns>
        public static long ConvertToUnixTimeMilliseconds(this DateTime date)
        {
            var dateTimeOffset = new DateTimeOffset(date);
            var unixDateTime = dateTimeOffset.ToUnixTimeMilliseconds();
            return unixDateTime;
        }
 
        /// <summary>
        /// Using DateTimeOffset
        /// </summary>
        /// <param name="date"></param>
        /// <returns></returns>
        public static long ConvertToUnixTimeSeconds(this DateTime date)
        {
            var dateTimeOffset = new DateTimeOffset(date);
            var unixDateTime = dateTimeOffset.ToUnixTimeSeconds();
            return unixDateTime;
        }
 
        /// <summary>
        /// Using .ToUniversalTime().Subtract
        /// </summary>
        /// <param name="date"></param>
        /// <returns></returns>
        public static long ToUnixTimeMilliseconds(this DateTime date)
        {
            return (long)(date.ToUniversalTime().Subtract(new DateTime(1970, 1, 1))).TotalMilliseconds;
        }
 
        /// <summary>
        /// Using .ToUniversalTime().Subtract
        /// </summary>
        /// <param name="date"></param>
        /// <returns></returns>
        public static long ToUnixTimeSeconds(this DateTime date)
        {
            return (long)(date.ToUniversalTime().Subtract(new DateTime(1970, 1, 1))).TotalSeconds;
        }
    }
 
    public class Program
    {
        private static void Main(string[] args)
        {
            long unixTimestamp = (long)DateTime.UtcNow.Subtract(new DateTime(1970, 1, 1)).TotalMilliseconds;
            Console.WriteLine($"UnixTimestamp: \t\t\t{unixTimestamp}");
 
            Console.WriteLine($"GetUnixTimeMilliseconds: \t{DateTimeHelper.GetUnixTimeMilliseconds()}");
            Console.WriteLine($"ConvertToUnixTimeMilliseconds: \t{DateTimeHelper.ConvertToUnixTimeMilliseconds()}");
 
            Console.WriteLine($"GetUnixTimeSeconds: \t\t{DateTimeHelper.GetUnixTimeSeconds()}");
            Console.WriteLine($"ConvertToUnixTimeSeconds: \t{DateTimeHelper.ConvertToUnixTimeSeconds()}");
        }
    }
}