c# 多線程代碼之美設計與應用

# 多線程控制的方法有很多種，然而如何優雅地控制多線程卻是門學問。筆者一直也糾結於此，失敗的多線程設計絕對是畫虎不成反類貓，不但沒有提高性能，效率反而會更低。

下面的一段代碼使用了信號量對多線程進行控制pdf，希望讀到的朋友能體會到優雅的代碼所帶來的樂趣。也希望高手們提供更高明的方法。

using System;
using System.Threading;

namespace MyLab
{
    public delegate void handler(object obj);

    public class Program
    {
        /// <summary>
        /// pdf信號量用於控制最大併發線程數
        /// </summary>
        private static Semaphore pool;
        /// <summary>
        /// pdf用於控制暫停、繼續
        /// </summary>
        private static ManualResetEvent status;

        private static int count = 0;

        private static int num = 50;

        public Program()
        {
            status = new ManualResetEvent(false);
        }

        public static void QueueWorkItem(handler ihandler, object args)
        {

            Thread t = new Thread(delegate()
            {
                runThread(ihandler, args);
            });

            count++;
            t.Name = string.Format("thread {0}", count);
            t.Start();
        }

        public static void runThread(handler ihandler,object arg)
        {
            status.WaitOne();
            pool.WaitOne();
            ihandler(arg);

            do
            {
                status.WaitOne();
                if (bStoped)
                {
                    Thread.CurrentThread.Abort();
                }
            }
            while (bPause);

            pool.Release();
        }

        public static void Main()
        {
            Application.Run(new Form1());
        }

        public static bool bStart = false;
        public static bool bStoped = false;
        public static bool bPause = false;

        public static void Run()
        {
            if (bStart)
            {
                pool.Release(num);
                status.Set();
                bStart = false;
            }
        }

        public void Start(int _num)
        {
            bStart = true;
            num = _numpdf;
            pool = new Semaphore(0, _num);
            Thread t = new Thread(delegate() { Run(); });
            t.Start()pdf;
        }

        public void Pause()
        {
            bPause = true;
            status.Reset();
        }

        public void Resume()
        {
            bPause = false;
            status.Set();
        }

        public void Stop()
        {
            status.Reset();
            bStoped = true;

        }

    }
}