C#线程池

    C#编程中如果想要实现多线程，我们可以自己新建Thread，也可以使用C#自带的ThreadPool（它提供一个线程池，该线程池可用于发送工作项、处理异步 I/O、代表其他线程等待以及处理计时器）。现在提供两个例子（控制台程序和窗体程序）：

控制台程序：

public class Fibonacci
    {
        public Fibonacci(int n, ManualResetEvent doneEvent)
        {
            _n = n;
            _doneEvent = doneEvent;
        }

        //Wrapper method for use with thread pool

        public void ThreadPoolCallback(Object threadContext)
        {
            int threadIndex = (int)threadContext;
            Console.WriteLine("thread {0} started...", threadIndex);
            _fibOfN = Calculate(_n);
            Console.WriteLine("thread {0} result calculated...", threadIndex);
            _doneEvent.Set();
        }

        public int Calculate(int n)
        {
            if (n <= 1)
            {
                return n;
            }
            return Calculate(n - 1) + Calculate(n - 2);
        }
        public int N { get { return _n; } }
        public int FibOfN { get { return _fibOfN; } }

        private int _n;
        private int _fibOfN;
        private ManualResetEvent _doneEvent;
    }
    class Program
    {
        static void Main(string[] args)
        {
            const int FibonacciCaculations = 10;
            //One event is used for each Fibonacci object

            ManualResetEvent[] doneEvents = new ManualResetEvent[FibonacciCaculations];
            Fibonacci[] fibArray = new Fibonacci[FibonacciCaculations];
            Random r = new Random();
            //开始使用线程池

            Console.WriteLine("launching {0} tasks...", FibonacciCaculations);
            for (int i = 0; i < FibonacciCaculations; i++)
            {
                doneEvents[i] = new ManualResetEvent(false);
                Fibonacci f = new Fibonacci(r.Next(20, 40), doneEvents[i]);
                fibArray[i] = f;
                ThreadPool.QueueUserWorkItem(f.ThreadPoolCallback, i);
            }
            //等待线程池中所有计算完成

            WaitHandle.WaitAll(doneEvents);
            Console.WriteLine("All calculations are complete.");
            //Display the results

            for (int i = 0; i < FibonacciCaculations; i++)
            {
                Fibonacci f = fibArray[i];
                Console.WriteLine("Fibonacci({0}) = {1}", f.N, f.FibOfN);
            }
            Console.Read();
        }
    }

窗体程序：

①多线程管理类

//用于显示状态的代理方法类型定义

    public delegate void DelegateShowStateInfo(string state);

    ///

    /// 测试器

    ///

    public class QueueTester
    {
        private static bool _Exit = false; //标记是否已中断测试程序

        private static Form _OwnerForm; //测试的窗体

        private static DelegateShowStateInfo _StateMethod;

        private static IList _Queue1 = new ArrayList(); //Queue1的数据

        private static IList _Queue2 = new ArrayList(); //Queue2的数据

        private static IList _Queue3 = new ArrayList(); //Queue3的数据



        public static void StopThread()
        {
            _Exit = true;
            _OwnerForm = null;
        }

        public static void Testing(Form sender, DelegateShowStateInfo method)
        {
            _StateMethod = method;
            _OwnerForm = sender;
            _Exit = false;

            ThreadPool.QueueUserWorkItem(MainTestThread);
            ThreadPool.QueueUserWorkItem(Queue1Thread); //启动Queue1线程

            ThreadPool.QueueUserWorkItem(Queue2Thread); //启动Queue2线程

        }

        //测试用的主线程，循环向队列1压入数据。

        public static void MainTestThread(object state)
        {
            Random R = new Random(1);
            double V = 0;

            while (_Exit == false)
            {
                //在while（true）里一直对数据进行读取，然后放到queue1中，

                //与此同时如果queue1中有数据，则线程1就开启


                //随机数

                V = R.NextDouble();

                _Queue1.Add(V); //把数据插入到队列1

                Application.DoEvents();

                ShowState();

                Thread.Sleep(100);//生成随机数太快,为了看清效果,暂停n毫秒

            }
        }


        //对queue1中的数据进行处理，处理后放到queue2中

        public static void Queue1Thread(object state)
        {
            while (_Exit == false)
            {
                while (_Queue1.Count > 0)
                {
                    //对queue1中的数据进行处理，处理后放到queue2中

                    _Queue2.Add(_Queue1[0]);
                    _Queue1.RemoveAt(0);
                    Application.DoEvents();

                    ShowState();
                }
            }
        }

        //对queue2中的数据进行处理，处理后放到queue3中

        public static void Queue2Thread(object state)
        {
            while (_Exit == false)
            {
                while (_Queue2.Count > 0)
                {
                    //对queue1中的数据进行处理，处理后放到queue2中

                    _Queue3.Add(_Queue2[0]);
                    _Queue2.RemoveAt(0);
                    Application.DoEvents();

                    ShowState();
                }
            }
        }

        //用于监视各队列状态的线程

        public static void ShowState()
        {
            string stateInfo =
                QueueTester._Queue1.Count.ToString() + " -> " +
                QueueTester._Queue2.Count.ToString() + " -> " +
                QueueTester._Queue3.Count.ToString();

            try
            {
                if (_OwnerForm != null)
                {
                    _OwnerForm.Invoke(_StateMethod, stateInfo);
                    Application.DoEvents();
                }
            }
            catch
            {

            }
        }

    }

窗体代码：见附件

 frmQueueTest.rar