來自:www.kunwsoft.com 以前在使用VB來實現(xiàn)多線程的時候,發(fā)現(xiàn)有一定的難度。雖然也有這樣那樣的方法,但都不盡人意,但在C#中,要編寫多線程應用程序卻相當?shù)暮唵巍_@篇文章將作簡要的介紹,以起到拋磚引玉的作用! .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,在殺死一個線程前最好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.
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