C#中多线程使用Thead和ThreadPool比较

1. 利用Thread start启动线程

ThreadStart表示执行线程的方法

ThreadStart(delegate(){})

        public static void testThread()        {            int Max_Thread_Count = 10;            long currentThreadCount = 0;            for(var i = 0;i < 100;i ++)            {                var ii = i;                while(true)                {                    if (Interlocked.Read(ref currentThreadCount) < Max_Thread_Count)                        break;                    Thread.Sleep(1000);                }                Interlocked.Increment(ref currentThreadCount);                new Thread(new ThreadStart(delegate()                    {                        Thread.Sleep(1000);                        Console.WriteLine("Current position is " + ii);                        Thread.Sleep(1000);                        Interlocked.Decrement(ref currentThreadCount);                    })).Start();            }            while (true)            {                Console.WriteLine("Running thread count " + currentThreadCount);                if (Interlocked.Read(ref currentThreadCount) == 0)                    break;                Thread.Sleep(1000);            }        }

ThreadStart(方法名)

        public static void testThread()        {            int Max_Thread_Count = 10;            long currentThreadCount = 0;            for(var i = 0;i < 100;i ++)            {                var ii = i;                while(true)                {                    if (Interlocked.Read(ref currentThreadCount) < Max_Thread_Count)                        break;                    Thread.Sleep(1000);                }                Interlocked.Increment(ref currentThreadCount);                new Thread(new ThreadStart(DoWork)).Start();                //new Thread(new ThreadStart(Work.DoWork)).Start();                Interlocked.Decrement(ref currentThreadCount);            }            while (true)            {                Console.WriteLine("Running thread count " + currentThreadCount);                if (Interlocked.Read(ref currentThreadCount) == 0)                    break;                Thread.Sleep(1000);            }        }        public static void DoWork()        {            Console.WriteLine("Static thread procedure.");        }        class Work        {            public static void DoWork()            {                Console.WriteLine("Static thread procedure.");            }            public int Data;            public void DoMoreWork()            {                Console.WriteLine("Instance thread procedure. Data={0}", Data);            }        }

2. 利用ThreadPool QueueUserWorkItem执行多线程

        public static void testThread()        {            int Max_Thread_Count = 10;            var semaphore = new Semaphore(Max_Thread_Count, Max_Thread_Count);            for(var i = 0;i < 100;i ++)            {                var ii = i;                ThreadPool.QueueUserWorkItem(                    (state0) =>                    {                        semaphore.WaitOne();                        Thread.Sleep(2000);                        Console.WriteLine("Process " + ii);                        semaphore.Release();                    }                    );            }        }

http://stackoverflow.com/questions/3334178/limit-threads-count

3. 两种方法的主要区别

这个里面的分析比较好： http://stackoverflow.com/questions/6192898/thread-start-versus-threadpool-queueuserworkitem

Starting a new thread can be a very expensive operation. The thread pool reuses threads and thus amortizes the cost. Unless you need a dedicated thread, the thread pool is the recommended way to go. By using a dedicated thread you have more control over thread specific attributes such as priority, culture and so forth. Also, you should not do long running tasks on the thread pool as it will force the pool to spawn additional threads.

In addition to the options you mention .NET 4 offers some great abstractions for concurrency. Check out the Task and Parallel classes as well as all the new PLINQ methods.

ThreadPool可以重复利用线程，因而更省成本。Thread start直接用起来更方便点。