VisualC#中編寫多線程程序之起步

.net將關于多線程的功能定義在System.Threading名字空間中。因此，要使用多線程，必須先聲明引用此名字空間（using System.Threading;）。
    即使你沒有編寫多線程應用程序的經(jīng)驗，也可能聽說過“啟動線程”“殺死線程”這些詞，其實除了這兩個外，涉及多線程方面的還有諸如“暫停線程”“優(yōu)先級”“掛起線程”“恢復線程”等等。下面將一個一個的解釋。
    a.啟動線程
    顧名思義，“啟動線程”就是新建并啟動一個線程的意思，如下代碼可實現(xiàn)：
    Thread thread1 = new Thread(new ThreadStart( Count));
    其中的 Count 是將要被新線程執(zhí)行的函數(shù)。
    b.殺死線程
    “殺死線程”就是將一線程斬草除根，為了不白費力氣，在殺死一個線程前先判斷它是否還活著（通過 IsAlive 屬性），然后就可以調(diào)用 Abort 方法來殺死此線程。
    c.暫停線程
    它的意思就是讓一個正在運行的線程休眠一段時間。如 thread.Sleep(1000); 就是讓線程休眠1秒鐘。
    d.優(yōu)先級
    這個用不著解釋了。Thread類中有一個ThreadPriority屬性，它用來設置優(yōu)先級，但不能保證操作系統(tǒng)會接受該優(yōu)先級。一個線程的優(yōu)先級可 分為5種：Normal, AboveNormal, BelowNormal, Highest, Lowest。具體實現(xiàn)例子如下:
    thread.Priority = ThreadPriority.Highest;
    e.掛起線程
    Thread類的Suspend方法用來掛起線程，知道調(diào)用Resume，此線程才可以繼續(xù)執(zhí)行。如果線程已經(jīng)掛起，那就不會起作用。
    if (thread.ThreadState = ThreadState.Running)
    {
    thread.Suspend();
    }
    f.恢復線程
    用來恢復已經(jīng)掛起的線程，以讓它繼續(xù)執(zhí)行，如果線程沒掛起，也不會起作用。
    if (thread.ThreadState = ThreadState.Suspended)
    {
    thread.Resume();
    }
    下面將列出一個例子，以說明簡單的線程處理功能。此例子來自于幫助文檔。
    using System;
    using System.Threading;
    // Simple threading scenario: Start a static method running
    // on a second thread.
    public class ThreadExample {
    // The ThreadProc method is called when the thread starts.
    // It loops ten times, writing to the console and yielding
    // the rest of its time slice each time, and then ends.
    public static void ThreadProc() {
    for (int i = 0; i < 10; i++) {
    Console.WriteLine("ThreadProc: {0}", i);
    // Yield the rest of the time slice.
    Thread.Sleep(0);
    }
    }
    public static void Main() {
    Console.WriteLine("Main thread: Start a second thread.");
    // The constructor for the Thread class requires a ThreadStart
    // delegate that represents the method to be executed on the
    // thread. C# simplifies the creation of this delegate.
    Thread t = new Thread(new ThreadStart(ThreadProc));
    // Start ThreadProc. On a uniprocessor, the thread does not get
    // any processor time until the main thread yields. Uncomment
    // the Thread.Sleep that follows t.Start() to see the difference.
    t.Start();
    //Thread.Sleep(0);
    for (int i = 0; i < 4; i++) {
    Console.WriteLine("Main thread: Do some work.");
    Thread.Sleep(0);
    }
    Console.WriteLine("Main thread: Call Join(), to wait until ThreadProc ends.");
    t.Join();
    Console.WriteLine("Main thread: ThreadProc.Join has returned. Press Enter to end program.");
    Console.ReadLine();
    }
    }
    此代碼產(chǎn)生的輸出類似如下內(nèi)容：
    Main thread: Start a second thread.
    Main thread: Do some work.
    ThreadProc: 0
    Main thread: Do some work.
    ThreadProc: 1
    Main thread: Do some work.
    ThreadProc: 2
    Main thread: Do some work.
    ThreadProc: 3
    Main thread: Call Join(), to wait until ThreadProc ends.
    ThreadProc: 4
    ThreadProc: 5
    ThreadProc: 6
    ThreadProc: 7
    ThreadProc: 8
    ThreadProc: 9
    Main thread: ThreadProc.Join has returned. Press Enter to end program