C#コンソールカウントダウンの詳しい説明

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

namespace Timer
{
    class Program
    {
        static bool isEnd = false;

        static void Main(string[] args)
        {
            //控制台标题
            Console.Title = "Timer";
            //控制台宽度
            Console.WindowWidth = 50;
            //控制台高度25是最低
            Console.BufferHeight = 25;
            Console.WriteLine("现在的时间是");
            Console.WriteLine(DateTime.Now);
            Console.WriteLine("输入截至时间");

            //获取设定时间
            DateTime dt = Convert.ToDateTime(Console.ReadLine());
            //获取开始时间
            DateTime dtNow = Convert.ToDateTime(DateTime.Now);


            //调用线程获取时间
            while (isEnd == false)
            {
                Thread thread = new Thread(delegate() { GetTime(dt); });
                thread.Start();
                Thread.Sleep(1000);
            }
            Console.ReadLine();
        }



        //输出计时剩余时间
        static void GetTime(DateTime dt)
        {
            //获取开始时间
            DateTime dtNow = Convert.ToDateTime(DateTime.Now);
            TimeSpan ts = dt - dtNow;
            Console.ForegroundColor = ConsoleColor.Green;
            Console.SetCursorPosition(8, 5);
            Console.WriteLine(ts);
            if (ts.TotalSeconds <= 1)
            {
                Console.SetCursorPosition(0, 9);
                Console.WriteLine("计时已完成");
                isEnd = true;
            }
        }
    }
}