簡(jiǎn)單易懂的C#.NET多線程應(yīng)用
.NET將關(guān)于多線程的功能定義在System.Threading名字空間中。因此,要實(shí)現(xiàn)C#.NET多線程應(yīng)用,必須先聲明引用此名字空間(using System.Threading;)。
即使你沒有編寫c#.net多線程應(yīng)用程序的經(jīng)驗(yàn),也可能聽說(shuō)過(guò)“啟動(dòng)線程”“殺死線程”這些詞,其實(shí)除了這兩個(gè)外,涉及多線程方面的還有諸如“暫停線程”“優(yōu)先級(jí)”“掛起線程”“恢復(fù)線程”等等。下面將一個(gè)一個(gè)的解釋。
a.啟動(dòng)線程
顧名思義,“啟動(dòng)線程”就是新建并啟動(dòng)一個(gè)線程的意思,如下代碼可實(shí)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(fèi)力氣,在殺死一個(gè)線程前***先判斷它是否還活著(通過(guò) IsAlive 屬性),然后就可以調(diào)用 Abort 方法來(lái)殺死此線程。
c.暫停線程
它的意思就是讓一個(gè)正在運(yùn)行的線程休眠一段時(shí)間。如 thread.Sleep(1000); 就是讓線程休眠1秒鐘。
d.優(yōu)先級(jí)
這個(gè)用不著解釋了。Thread類中有一個(gè)ThreadPriority屬性,它用來(lái)設(shè)置優(yōu)先級(jí),但不能保證操作系統(tǒng)會(huì)接受該優(yōu)先級(jí)。一個(gè)線程的優(yōu)先級(jí)可分為5種:Normal, AboveNormal, BelowNormal, Highest, Lowest。具體實(shí)現(xiàn)例子如下:
- thread.Priority = ThreadPriority.Highest;
e.掛起線程
Thread類的Suspend方法用來(lái)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(huì)起作用。
- if (thread.ThreadState = ThreadState.Running)
- {
- thread.Suspend();
- }
f.恢復(fù)線程
用來(lái)恢復(fù)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(huì)起作用。
- if (thread.ThreadState = ThreadState.Suspended)
- {
- thread.Resume();
- }
下面將列出一個(gè)例子,以說(shuō)明簡(jiǎn)單的線程處理功能。此例子來(lái)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.
C#.NET多線程應(yīng)用的相關(guān)知識(shí)就介紹到這里,是不是非常簡(jiǎn)單呢?
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