非UI的子線程再啟動線程的話，等待的時候會被阻塞，Task不會阻塞了

需要在.Net 4.0才會有Task

當然，既然接觸到了Task，或許以后就不再用線程了，具體看情況了，之前幾個線程之間就發生了阻塞問題，這次就是要解決這個問題才下這個功夫的，否則寧可被差遣抱兒子尿尿去。

using System;  
using System.Collections.Generic;  
using System.Linq;  
using System.Text;  
 
using System.Threading.Tasks;  
using System.Threading;  
 
namespace TaskDemo  
{  
    class Program  
    {  
        static void Main(string[] args)  
        {  
            Thread mTH = new Thread(RunTask);  
            mTH.Start();  
 
            //Thread mTH1 = new Thread(RunThread);  
            //mTH1.Start();  
        }  
 
        private static void RunThread()  
        {  
            for (int i = 0; i < 20; i++)  
            {  
                Thread.Sleep(2);  
                Console.WriteLine("RunThread{0}", i);  
            }  
        }  
 
        private static void RunTask()  
        {  
            try 
            {  
                int mCount = 0;  
 
                CancellationTokenSource tokenSource = new CancellationTokenSource();  
                CancellationToken token = tokenSource.Token;  
 
                Task t = new Task(() =>  
                {  
                    Console.WriteLine("進入任務……");  
                    Thread.Sleep(10);  
                    Console.WriteLine("任務開始工作……");  
                    //模擬工作過程     
                    for (int i = 0; i < 20; i++)  
                    {  
                        if (token.IsCancellationRequested == true)  
                        {  
                            break;          //這里別人是用一個throw new OperationCanceledException(token); 但是我用就會報錯  
                        }  
                        mCount++;  
                        Console.WriteLine("RunTask{0}", i);  
                        Thread.Sleep(1);  
                    }  
                }, token);  
                token.Register(() =>  
               {  
                   Console.WriteLine("Canceled");  
 
               });  
                t.Start();  
                Console.WriteLine("這條語句先運行完畢了……");  
                t.ContinueWith((task) =>  
                {  
                    Console.WriteLine("任務完成，完成時候的狀態為：");  
                    Console.WriteLine("IsCanceled={0}\tIsCompleted={1}\tIsFaulted={2}\tmCount={3}", task.IsCanceled, task.IsCompleted, task.IsFaulted, mCount);  
                });  
                Console.WriteLine("現在就按任意鍵的話，程序就退出了……");  
 
                RunThread();        //線程內部較耗時的測試  
 
                Console.ReadKey();      //由于兩個sleep都有點時間，如果在這時間之前按下任意鍵，結果是程序提前終止了  
                tokenSource.Cancel();  
                Console.ReadKey();      //程序退出  
 
            }  
            catch (Exception Ex)  
            {  
                Console.WriteLine(Ex.Message);  
            }  
        }  
 
    }  
}