C#学习系列相关之多线程（五）----线程池ThreadPool用法

ThreadPool.QueueUserWorkItem(WaitCallback(DoWork), object)

public delegate void WaitCallback(object state);

codepublic static void DoWork(object state)
{
    // 执行一些操作，使用传递进来的状态对象
}
static void Main(string[] args)
{
    // 将 DoWork 方法添加到线程池中
    ThreadPool.QueueUserWorkItem(new WaitCallback(DoWork), someStateObject);
}

// 参数:
        // workerThreads:
        // 要由线程池根据需要创建的新的最小工作程序线程数。
        // completionPortThreads:
        // 要由线程池根据需要创建的新的最小空闲异步 I/O 线程数。
        // 返回结果:如果更改成功，则为 true；否则为 false。
        [SecuritySafeCritical]
        public static bool SetMinThreads(int workerThreads, int completionPortThreads);
        // 参数:
        // workerThreads:
        // 线程池中辅助线程的最大数目。
         // completionPortThreads:
        // 线程池中异步 I/O 线程的最大数目。
        // 返回结果:如果更改成功，则为 true；否则为 false。
        [SecuritySafeCritical]
        public static bool SetMaxThreads(int workerThreads, int completionPortThreads)
例如：
            ThreadPool.SetMinThreads(1,1);
            ThreadPool.SetMaxThreads(5, 5);

using System;
using System.Threading;
public class Example
{
    // mre is used to block and release threads manually. It is
    // created in the unsignaled state.
    private static ManualResetEvent mre = new ManualResetEvent(false);
    static void Main()
    {
        Console.WriteLine("\nStart 3 named threads that block on a ManualResetEvent:\n");
    //中文注释1：开启三个线程，每个线程开启后调用WaitOne()阻塞。
        for(int i = 0; i <= 2; i++)
        {
            Thread t = new Thread(ThreadProc);
            t.Name = "Thread_" + i;
            t.Start();
        }
        Thread.Sleep(500);
        Console.WriteLine("\nWhen all three threads have started, press Enter to call Set()" +
                          "\nto release all the threads.\n");
        Console.ReadLine();
    //中文注释2：只有当Set()后才会执行WaitOne()后的代码
        mre.Set();
        Thread.Sleep(500);
        Console.WriteLine("\nWhen a ManualResetEvent is signaled, threads that call WaitOne()" +
                          "\ndo not block. Press Enter to show this.\n");
        Console.ReadLine();
    //中文注释3：继续再开两个线程，仍然调用WaitOne(),但是不会阻塞，会继续执行
        for(int i = 3; i <= 4; i++)
        {
            Thread t = new Thread(ThreadProc);
            t.Name = "Thread_" + i;
            t.Start();
        }
        Thread.Sleep(500);
        Console.WriteLine("\nPress Enter to call Reset(), so that threads once again block" +
                          "\nwhen they call WaitOne().\n");
        Console.ReadLine();
    //中文注释4：只有Reset()后，下面再开线程就会继续被阻塞
        mre.Reset();
        // Start a thread that waits on the ManualResetEvent.
        Thread t5 = new Thread(ThreadProc);
        t5.Name = "Thread_5";
        t5.Start();
        Thread.Sleep(500);
        Console.WriteLine("\nPress Enter to call Set() and conclude the demo.");
        Console.ReadLine();
    //中文注释5：再次Set(),就可以了
        mre.Set();
        // If you run this example in Visual Studio, uncomment the following line:
        //Console.ReadLine();
    }
    private static void ThreadProc()
    {
        string name = Thread.CurrentThread.Name;
        Console.WriteLine(name + " starts and calls mre.WaitOne()");
        mre.WaitOne();
        Console.WriteLine(name + " ends.");
    }
}
/* This example produces output similar to the following:
Start 3 named threads that block on a ManualResetEvent:
Thread_0 starts and calls mre.WaitOne()
Thread_1 starts and calls mre.WaitOne()
Thread_2 starts and calls mre.WaitOne()
When all three threads have started, press Enter to call Set()
to release all the threads.
Thread_2 ends.
Thread_0 ends.
Thread_1 ends.
When a ManualResetEvent is signaled, threads that call WaitOne()
do not block. Press Enter to show this.
Thread_3 starts and calls mre.WaitOne()
Thread_3 ends.
Thread_4 starts and calls mre.WaitOne()
Thread_4 ends.
Press Enter to call Reset(), so that threads once again block
when they call WaitOne().
Thread_5 starts and calls mre.WaitOne()
Press Enter to call Set() and conclude the demo.
Thread_5 ends.

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
 
namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            const int times = 10;  //开线程数
            ManualResetEvent[] mre = new ManualResetEvent[times];   //1、定义开线程数
            Random random = new Random();   //随机数
            Console.WriteLine("开始 {0} 任务", times);
            for (int i = 0; i < times; i++)   //2、循环这10个线程
            {
                mre[i] = new ManualResetEvent(false);  //3、初始化每个线程：设置false表示无信号，将使WaitOne阻塞也就是线程等待
                count c = new count(random.Next(1, 1000), mre[i]);   //借助类传参
                ThreadPool.QueueUserWorkItem(c.ThreadPoolCallback, i);   //4、为每个线程安排任务
 
            }
            WaitHandle.WaitAll(mre);    //6、让主线程等待所有线程完成（池中线程数不能多于64个）
            Console.WriteLine("所有线程完成！");
            Console.Read();
        }
    }
 
    class count
    {
        private int ramNum;   //存放随机数
        private ManualResetEvent threadSta;   //线程状态
        private int total;    //存放线程计算结果
 
        /// <summary>
        /// 传递数据
        /// </summary>
        /// <param name="ramnum">保存随机数</param>
        /// <param name="mre">线程状态</param>
        public count(int ramnum, ManualResetEvent mre)
        {
            ramNum = ramnum;
            threadSta = mre;
        }
 
        /// <summary>
        /// 线程
        /// </summary>
        /// <param name="threadParam"></param>
        public void ThreadPoolCallback(Object threadParam)
        {
            int threadIndex = (int)threadParam;
            Console.WriteLine("线程 {0} 启动", threadIndex);
            total = docount(ramNum);
            Console.WriteLine("线程执行结果： {0}", total);
            threadSta.Set();  //5、设置每个线程为有信号状态：通知WaitOne不再阻塞
        }
 
        /// <summary>
        /// 从0开始加到传过来数
        /// </summary>
        /// <param name="ramNum">传过来的数：产生的随机数</param>
        /// <returns>返回相加的结果</returns>
        public int docount(int ramNum)
        {
            int sum = 0;
            for (int i = 0; i <= ramNum; i++)
            {
                sum += i;
            }
            return sum;
        }
    }
}