应朋友之邀，写了一个多线程执行多任务的例子。这个场景应用比较普遍，

比如多个线程下载多个文件，比如3个线程下载10个文件，比如10个线程执行1000条任务队列；

Demo代码如下：

public partial class Form1 : Form
    {
        private ThreadProxy _threadsProxy = null;
        ExpressCollection list = new ExpressCollection();

        public Form1()
        {
            InitializeComponent();

            _threadsProxy = new ThreadProxy(3, list);
            _threadsProxy.ExpressComputed += new EventHandler<ExpressComputedEventArgs>(_threadsProxy_ExpressComputed);
        }

        private void button1_Click(object sender, EventArgs e)
        {
            list.Clear();
            _threadsProxy.Stop();
            list.Add(new Express(1, 1));
            list.Add(new Express(1, 2));
            list.Add(new Express(1, 3));
            list.Add(new Express(1, 4));
            list.Add(new Express(1, 5));
            list.Add(new Express(1, 6));
            list.Add(new Express(1, 7));
            list.Add(new Express(1, 8));
            list.Add(new Express(1, 9));
            list.Add(new Express(1, 10));
            list.Add(new Express(1, 11));
            list.Add(new Express(1, 12));
            list.Add(new Express(1, 13));
            list.Add(new Express(1, 14));
            Console.WriteLine("启动线程...........................");
            _threadsProxy.Run();
        }

        private void button2_Click(object sender, EventArgs e)
        {
            if (_threadsProxy != null)
            {
                Console.WriteLine("测试暂停...........................");
                _threadsProxy.Stop();
            }
        }

        void _threadsProxy_ExpressComputed(object sender, ExpressComputedEventArgs e)
        {
            Console.WriteLine(string.Format("ThreadID:{0}  {1} + {2} = {3}", Thread.CurrentThread.ManagedThreadId, e.Express.A, e.Express.B, e.Result));
        }
    }

    public class ThreadProxy : IDisposable
    {
        private int _threadCount = 1;
        ExpressCollection _list;
        private Thread[] _threads = null;
        private bool _isRun = false;

        public ThreadProxy(ExpressCollection list)
        {
            _list = list;
        }

        public ThreadProxy(int threadCount, ExpressCollection list)
            : this(list)
        {
            _threadCount = threadCount;
            _threads = CreateThreadCollection();
        }

        public void Run()
        {
            if (!_isRun && _list != null && _list.Count>0)
            {
                _isRun = true;
                for (int i = 0; i < _threadCount; i++)
                {
                    _threads[i] = new Thread(new ThreadStart(ThreadInvoke));
                    _threads[i].IsBackground = true;
                    _threads[i].Start();
                }
            }
        }

        protected virtual Thread[] CreateThreadCollection()
        {
            return new Thread[_threadCount];
        }

        public void Stop()
        {
            _isRun = false;
        }

        private void ThreadInvoke()
        {
            try
            {
                while (_isRun)
                {
                    Express express = _list.GetNext();
                    if (express != null)
                    {
                        int result = express.A + express.B;
                        OnExpressComputed(result, express);
                        //do something
                        Thread.Sleep(1000);//测试暂停
                    }
                    else
                    {
                        break;
                    }
                }
            }
            catch (ThreadAbortException)
            {
                Thread.ResetAbort();
                return;
            }
            catch (Exception)
            {
                //记录日志
            }
        }

        public event EventHandler<ExpressComputedEventArgs> ExpressComputed;

        protected virtual void OnExpressComputed(int result ,Express express)
        {
            if (ExpressComputed != null)
            {
                ExpressComputed(this, new ExpressComputedEventArgs(result,express));
            }
        }

        #region IDisposable 成员

        public void Dispose()
        {
            _isRun = false;
            if (_threads != null)
            {
                _threads = null;
            }
        }

        #endregion
    }

    public class ExpressComputedEventArgs : EventArgs
    {
        private int result;

        public int Result
        {
            get { return result; }
            set { result = value; }
        }

        public ExpressComputedEventArgs(int result , Express express)
        {
            this.result = result;
            this.express = express;
        }

        private Express express;

        public Express Express
        {
            get { return express; }
            set { express = value; }
        }
    }

public class BaseCollection<T> : List<T>
    {
        protected readonly object _lockObj = new object();

        private int index = 0;
        public virtual T GetNext()
        {
            T result = default(T);
            if (this.Count > 0 && index < Count)
            {
                lock (_lockObj)

                {
                    result = this[index];
                    index++;
                }
            }
            return result;
        }

        public new void Add(T item)
        {
            lock (_lockObj)
            {
                base.Add(item);
            }
        }

        public new void Clear()
        {
            lock (_lockObj)
            {
                index = 0;
                base.Clear();
            }
        }
    }

public class Express
    {
        private int _a;

        public int A
        {
            get { return _a; }
            set { _a = value; }
        }

        private int _b;

        public int B
        {
            get { return _b; }
            set { _b = value; }
        }

        public Express(int a, int b)
        {
            _a = a;
            _b = b;
        }
    }

public class ExpressCollection : BaseCollection<Express>
   {

   }