WaitHandle.WaitAny()的错误

Question

using System;
using System.Collections.Generic;
using System.Text;
using System.Threading ;namespace charpter18
{
    public struct InputData
    {
        public int x;
        public int y;
        public InputData(int x, int y)
        {
            this.x = x;
            this.y = y;
        }
    }
    public class ThreadTask
    {
        private AutoResetEvent autoEvent;
        private int result;
        public int Result
        {
            get
            {
                return result;
            }
        }
        public ThreadTask(AutoResetEvent ev)
        {
            this.autoEvent = ev;
        }
        public void Calculation(object obj)
        {
            InputData data = (InputData)obj;
            Console.WriteLine("Thread {0} starts calculation", Thread.CurrentThread.ManagedThreadId);
            Thread.Sleep(new Random().Next(3000));
            autoEvent.Set();
        }
    }
    class Events1
    {
        static void Main()
        {
            int taskCount = 4;
            AutoResetEvent[] autoEvents = new AutoResetEvent[taskCount];
            ThreadTask[] tasks = new ThreadTask[taskCount];
            for (int i = 0; i < taskCount; i++)
            {
                autoEvents[i] = new AutoResetEvent(false);
                tasks[i] = new ThreadTask(autoEvents[i]);
                ThreadPool.QueueUserWorkItem(tasks[i].Calculation, new InputData(i + 1, i + 3));
            }
            for (int i = 0; i < taskCount; i++)
            {
                int index = WaitHandle.WaitAny(autoEvents);
                if (index == WaitHandle.WaitTimeout)
                {
                    Console.WriteLine("Timeout!!");
                }
                else
                {
                    Console.WriteLine("finished task for{0}, result:{1}", index, tasks[index].Result);
                }
            }
        }
    }
}为什么有颜色的部分提示错误了  请各位帮忙看看 谢谢