c# 多線程代碼之美

c# 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，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>
/// 信號量用於控制最大並發線程數
/// </summary>
private static Semaphore pool;
/// <summary>
/// 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 = _num;
pool = new Semaphore(0, _num);
Thread t = new Thread(delegate() { Run(); });
t.Start();
}

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

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

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

}

}
}