c#中Thread.Join()方法的经典示例
在 C# 中，Thread.Join 是一个非常有用的方法，它可以让主线程（调用线程）等待子线程（被调用线程）执行完毕后再继续执行。
1、经典示例1
using System;
using System.Threading;public class Example
{static Thread thread1, thread2;public static void Main(){thread1 = new Thread(ThreadProc);thread1.Name = "Thread1";thread1.Start();thread2 = new Thread(ThreadProc);thread2.Name = "Thread2";thread2.Start();Console.ReadKey();}private static void ThreadProc(){Console.WriteLine("\nCurrent thread: {0}", Thread.CurrentThread.Name);if (Thread.CurrentThread.Name == "Thread1" &&thread2.ThreadState != ThreadState.Unstarted){Console.WriteLine("thread2.Join");thread2.Join(); }Thread.Sleep(1000);Console.WriteLine("\nCurrent thread: {0}", Thread.CurrentThread.Name);Console.WriteLine("Thread1: {0}", thread1.ThreadState);Console.WriteLine("Thread2: {0}\n", thread2.ThreadState);}
}运行结果
Current thread: Thread1
thread2.JoinCurrent thread: Thread2Current thread: Thread2
Thread1: WaitSleepJoin
Thread2: RunningCurrent thread: Thread1
Thread1: Running
Thread2: Stopped这个例子演示了“Thread.Join 会阻塞调用线程，直到被调用线程完成执行”
2、经典示例2
using System.Threading;
using System;class TestThread
{private static void ThreadTst(){Console.WriteLine(" " + Thread.CurrentThread.Name + " 开始执行");for (int i = 0; i < 10; i++){Console.WriteLine(" " + Thread.CurrentThread.Name + " i = " + i);Thread.Sleep(10);}Console.WriteLine(" " + Thread.CurrentThread.Name + " 执行完毕");}static void Main(string[] args){//程序调用了Main()函数时,就起动了一个进程,同时也启动了一个线程[这个线程就是主线程].Thread.CurrentThread.Name = "MainThread";//创建第一个线程Thread tA = new Thread(new ThreadStart(TestThread.ThreadTst));tA.Name = "线程A";Thread tB = new Thread(new ThreadStart(TestThread.ThreadTst));tB.Name = "线程B";Thread tC = new Thread(new ThreadStart(TestThread.ThreadTst));tC.Name = "线程C";Thread tD = new Thread(new ThreadStart(TestThread.ThreadTst));tD.Name = "线程D";for (int z = 0; z < 20; z++){if (z == 3){Console.WriteLine("tA.Start");tA.Start();Console.WriteLine("tB.Start");tB.Start();}else if (z == 6){Console.WriteLine("tA.Join");tA.Join();Console.WriteLine("tB.Join");tB.Join();}else if (z == 9){Console.WriteLine("tC.Start");tC.Start();Console.WriteLine("tD.Start");tD.Start();}else{Console.WriteLine(Thread.CurrentThread.Name + " z = " + z);}}Console.Read();}
}
运行结果
MainThread z = 0
MainThread z = 1
MainThread z = 2
tA.Start
tB.Start
MainThread z = 4
MainThread z = 5
tA.Join线程A 开始执行线程A i = 0线程B 开始执行 ->注意这里并没有返回调用线程，这里是线程B线程B i = 0线程A i = 1线程B i = 1线程A i = 2线程B i = 2线程A i = 3线程B i = 3线程A i = 4线程B i = 4线程A i = 5线程B i = 5线程A i = 6线程B i = 6线程A i = 7线程B i = 7线程A i = 8线程B i = 8线程B i = 9线程A i = 9线程A 执行完毕线程B 执行完毕
tB.Join ->注意线程B已经执行完毕了
MainThread z = 7
MainThread z = 8
tC.Start
tD.Start
MainThread z = 10
MainThread z = 11
MainThread z = 12
MainThread z = 13
MainThread z = 14
MainThread z = 15
MainThread z = 16
MainThread z = 17
MainThread z = 18
MainThread z = 19线程C 开始执行 ->线程C是等主线程结束后才开始执行的线程C i = 0线程D 开始执行线程D i = 0线程C i = 1线程D i = 1线程C i = 2线程D i = 2线程C i = 3线程D i = 3线程C i = 4线程D i = 4线程C i = 5线程D i = 5线程C i = 6线程D i = 6线程C i = 7线程D i = 7线程C i = 8线程D i = 8线程C i = 9线程D i = 9线程C 执行完毕线程D 执行完毕这个例子主要目的是对比使用join（线程A、）和未使用join（线程C）的区别