C# -- 使用线程池 ThreadPool 执行多线程任务

1. 使用线程池

class Program
    {
        static void Main(string[] args)
        {
            WaitCallback wc1 = s =>{
                Console.WriteLine("线程ID:{0},开始执行", Thread.CurrentThread.ManagedThreadId);
                Stopwatch stw = new Stopwatch();
                stw.Start();
                long result = SumNumbers(10000000);
                stw.Stop();
                Console.WriteLine("线程ID:{0},执行完成,执行结果:{1},执行用时{2},",Thread.CurrentThread.ManagedThreadId,result,stw.ElapsedMilliseconds);
            };
            WaitCallback wc2 = s => {
                Console.WriteLine("线程ID:{0},开始执行", Thread.CurrentThread.ManagedThreadId);
                Stopwatch stw = new Stopwatch();
                stw.Start();
                long result = SumNumbers(10000000);
                stw.Stop();
                Console.WriteLine("线程ID:{0},执行完成,执行结果:{1},执行用时{2},", Thread.CurrentThread.ManagedThreadId, result, stw.ElapsedMilliseconds);
            };
            WaitCallback wc3 = s => {
                Console.WriteLine("线程ID:{0},开始执行", Thread.CurrentThread.ManagedThreadId);
                Stopwatch stw = new Stopwatch();
                stw.Start();
                long result = SumNumbers(10000000);
                stw.Stop();
                Console.WriteLine("线程ID:{0},执行完成,执行结果:{1},执行用时{2},", Thread.CurrentThread.ManagedThreadId, result, stw.ElapsedMilliseconds);
            };

            
            ThreadPool.QueueUserWorkItem(wc1);
            ThreadPool.QueueUserWorkItem(wc2);
            ThreadPool.QueueUserWorkItem(wc3);

            Console.ReadKey();
        }

        static long SumNumbers(int count)
        {
            long sum = 0;
            for (int i = 0; i < count; i++)
            {
                sum += i;
            }
            Thread.Sleep(1000);
            return sum;
        }
    }

执行结果：

2. 等待线程池的线程执行

class Program
    {
        static void Main(string[] args)
        {
            using (ManualResetEvent m1 = new ManualResetEvent(false))
            using (ManualResetEvent m2 = new ManualResetEvent(false))
            using (ManualResetEvent m3 = new ManualResetEvent(false))
            {
                ThreadPool.QueueUserWorkItem(
                    s =>{
                        Console.WriteLine("线程ID:{0},开始执行", Thread.CurrentThread.ManagedThreadId);
                        Stopwatch stw = new Stopwatch();
                        stw.Start();
                        long result = SumNumbers(10000000);
                        stw.Stop();
                        m1.Set();
                        Console.WriteLine("线程ID:{0},执行完成,执行结果:{1},执行用时{2},", Thread.CurrentThread.ManagedThreadId, result, stw.ElapsedMilliseconds);
                    });

                ThreadPool.QueueUserWorkItem(
                    s =>{
                        Console.WriteLine("线程ID:{0},开始执行", Thread.CurrentThread.ManagedThreadId);
                        Stopwatch stw = new Stopwatch();
                        stw.Start();
                        long result = SumNumbers(10000000);
                        stw.Stop();
                        m2.Set();
                        Console.WriteLine("线程ID:{0},执行完成,执行结果:{1},执行用时{2},", Thread.CurrentThread.ManagedThreadId, result, stw.ElapsedMilliseconds);
                    });
                ThreadPool.QueueUserWorkItem(
                    s =>{
                        Console.WriteLine("线程ID:{0},开始执行", Thread.CurrentThread.ManagedThreadId);
                        Stopwatch stw = new Stopwatch();
                        stw.Start();
                        long result = SumNumbers(10000000);
                        stw.Stop();
                        m3.Set();
                        Console.WriteLine("线程ID:{0},执行完成,执行结果:{1},执行用时{2},", Thread.CurrentThread.ManagedThreadId, result, stw.ElapsedMilliseconds);
                    });

                //等待线程池的线程执行
                m1.WaitOne();
                m2.WaitOne();
                m3.WaitOne();
                Console.WriteLine("所有线程执行完成");

            }

            Console.ReadKey();
        }

        static long SumNumbers(int count)
        {
            long sum = 0;
            for (int i = 0; i < count; i++)
            {
                sum += i;
            }
            Thread.Sleep(3000);
            return sum;
        }
    }

执行结果: