如果要判斷Thread執行完畢，才繼續執行程式，此時可以使用Join即可達到等待作用。

using System;
using System.Collections.Generic;
using System.Threading;

namespace Test
{
    class Program
    {
        static void Main(string[] args)
        {
            List<Thread> List_Thread = new List<Thread>();
            for (int i = 0; i < 10; i++)
            {
                //建立執行緒
                List_Thread.Add(new Thread((object x) =>
                {
                    int temp = 3;
                    while (temp-- > 0)
                    {
                        Console.WriteLine("Thread ID :" + x.ToString() + "\t" + temp.ToString());
                        System.Threading.Thread.Sleep(1000);
                    }
                }));
                List_Thread[i].Start(i + 1);
            }
            //等待所有執行緒完成
            foreach (Thread t in List_Thread) t.Join();
            Console.WriteLine("End");
        }
    }
}