public delegate void WaitCallback(object state);

    class Program
    {
        static void Main(string[] args)
        {
            ThreadPool.QueueUserWorkItem(MyAction);

            ThreadPool.QueueUserWorkItem(state =>
            {
                Console.WriteLine("任務(wù)已被執(zhí)行2");
            });
            Console.ReadKey();
        }
        // state 表示要傳遞的參數(shù)信息，這里為 null
        private static void MyAction(Object state)
        {
            Console.WriteLine("任務(wù)已被執(zhí)行1");
        }
    }

        static void Main()
        {
            Stopwatch watch = new Stopwatch();
            watch.Start();
            for (int i = 0; i < 10; i++)
                new Thread(() => { }).Start();
            watch.Stop();
            Console.WriteLine("創(chuàng)建 10 個(gè)線程需要花費(fèi)時(shí)間(毫秒)：" + watch.ElapsedMilliseconds);
            Console.ReadKey();
        }

// 設(shè)置線程池最小工作線程數(shù)線程
public static bool SetMinThreads (int workerThreads, int completionPortThreads);

// 獲取
public static void GetMinThreads (out int workerThreads, out int completionPortThreads);

// 設(shè)置線程池最大工作線程數(shù)
public static bool SetMaxThreads (int workerThreads, int completionPortThreads);

// 獲取
public static void GetMaxThreads (out int workerThreads, out int completionPortThreads);

    class Program
    {
        static void Main(string[] args)
        {
            // 不斷加入任務(wù)
            for (int i = 0; i < 8; i++)
                ThreadPool.QueueUserWorkItem(state =>
                {
                    Thread.Sleep(100);
                    Console.WriteLine("");
                });
            for (int i = 0; i < 8; i++)
                ThreadPool.QueueUserWorkItem(state =>
                {
                    Thread.Sleep(TimeSpan.FromSeconds(1));
                    Console.WriteLine("");
                });

            Console.WriteLine("     此計(jì)算機(jī)處理器數(shù)量：" + Environment.ProcessorCount);

            // 工作項(xiàng)、任務(wù)代表同一個(gè)意思
            Console.WriteLine("     當(dāng)前線程池存在線程數(shù)：" + ThreadPool.ThreadCount);
            Console.WriteLine("     當(dāng)前已處理的工作項(xiàng)數(shù)：" + ThreadPool.CompletedWorkItemCount);
            Console.WriteLine("     當(dāng)前已加入處理隊(duì)列的工作項(xiàng)數(shù)：" + ThreadPool.PendingWorkItemCount);
            int count;
            int ioCount;
            ThreadPool.GetMinThreads(out count, out ioCount);
            Console.WriteLine($"     默認(rèn)最小輔助線程數(shù)：{count}，默認(rèn)最小異步IO線程數(shù)：{ioCount}");

            ThreadPool.GetMaxThreads(out count, out ioCount);
            Console.WriteLine($"     默認(rèn)最大輔助線程數(shù)：{count}，默認(rèn)最大異步IO線程數(shù)：{ioCount}");
            Console.ReadKey();
        }
    }

     此計(jì)算機(jī)處理器數(shù)量：8
     當(dāng)前線程池存在線程數(shù)：8
     當(dāng)前已處理的工作項(xiàng)數(shù)：2
     當(dāng)前已加入處理隊(duì)列的工作項(xiàng)數(shù)：8
     默認(rèn)最小輔助線程數(shù)：8，默認(rèn)最小異步IO線程數(shù)：8
     默認(rèn)最大輔助線程數(shù)：32767，默認(rèn)最大異步IO線程數(shù)：1000

    class Program
    {
        private delegate string MyAsyncDelete(out int thisThreadId);
        static void Main(string[] args)
        {
            int threadId;
            // 不是異步調(diào)用
            MyMethodAsync(out threadId);

            // 創(chuàng)建自定義的委托
            MyAsyncDelete myAsync = MyMethodAsync;

            // 初始化異步的委托
            IAsyncResult result = myAsync.BeginInvoke(out threadId, null, null);

            // 當(dāng)前線程等待異步完成任務(wù)，也可以去掉
            result.AsyncWaitHandle.WaitOne();
            Console.WriteLine("異步執(zhí)行");

            // 檢索異步執(zhí)行結(jié)果
            string returnValue = myAsync.EndInvoke(out threadId, result);

            // 關(guān)閉
            result.AsyncWaitHandle.Close();

            Console.WriteLine("異步處理結(jié)果：" + returnValue);
        }
        private static string MyMethodAsync(out int threadId)
        {
            // 獲取當(dāng)前線程在托管線程池的唯一標(biāo)識(shí)
            threadId = Thread.CurrentThread.ManagedThreadId;
            // 模擬工作請(qǐng)求
            Thread.Sleep(TimeSpan.FromSeconds(new Random().Next(1, 5)));
            // 返回工作完成結(jié)果
            return "喜歡我的讀者可以關(guān)注筆者的博客歐~";
        }
    }

        CancellationTokenSource cts = new CancellationTokenSource();
        CancellationToken token = cts.Token;

    class Program
    {
        static void Main()
        {
            CancellationTokenSource cts = new CancellationTokenSource();

            Console.WriteLine("按下回車鍵，將取消任務(wù)");

            new Thread(() => { CanceTask(cts.Token); }).Start();
            new Thread(() => { CanceTask(cts.Token); }).Start();

            Console.ReadKey();
            
            // 取消執(zhí)行
            cts.Cancel();
            Console.WriteLine("完成");
            Console.ReadKey();
        }

        private static void CanceTask(CancellationToken token)
        {
            Console.WriteLine("第一階段");
            Thread.Sleep(TimeSpan.FromSeconds(1));
            if (token.IsCancellationRequested)
                return;

            Console.WriteLine("第二階段");
            Thread.Sleep(TimeSpan.FromSeconds(1));
            if (token.IsCancellationRequested)
                return;

            Console.WriteLine("第三階段");
            Thread.Sleep(TimeSpan.FromSeconds(1));
            if (token.IsCancellationRequested)
                return;

            Console.WriteLine("第四階段");
            Thread.Sleep(TimeSpan.FromSeconds(1));
            if (token.IsCancellationRequested)
                return;

            Console.WriteLine("第五階段");
            Thread.Sleep(TimeSpan.FromSeconds(1));
            if (token.IsCancellationRequested)
                return;
        }
    }

public Timer (System.Threading.TimerCallback callback, object state, uint dueTime, uint period);

    class Program
    {
        static void Main()
        {
            Timer timer = new Timer(TimeTask,null,100,1000);
            
            Console.ReadKey();
        }

        // public delegate void TimerCallback(object? state);
        private static void TimeTask(object state)
        {
            Console.WriteLine("www.whuanle.cn");
        }
    }