线程操作问题

[lshfong]

现有两个线程a和b，操作的是同一个文件，怎么样才能保证，a线程操作完毕后才启动b线程进行操作.

[wuxing2006]

lock

[lshfong]

详细一点，好吗，谢谢

[viena]

那何必用两个线程？
调用Join，可以阻塞当前线程直到那个线程结束

[lshfong]

还是不明白，给个例子好吗

[wenbin]

用AutoResetEvent 去做
详细资料可以查msdn

[wenbin]

using System;
using System.Threading;


class Resource {
Mutex m = new Mutex();

public void Access(Int32 threadNum) {
m.WaitOne();
try {
Console.WriteLine("Start Resource access (Thread={0})", threadNum);
Thread.Sleep(500);
Console.WriteLine("Stop Resource access (Thread={0})", threadNum);
}
finally {
m.ReleaseMutex();
}
}
}


class App {
static Int32 numAsyncOps = 5;
static AutoResetEvent asyncOpsAreDone = new AutoResetEvent(false);
static Resource res = new Resource();

public static void Main() {
for (Int32 threadNum = 0; threadNum < 5; threadNum++) {
ThreadPool.QueueUserWorkItem(new WaitCallback(UpdateResource), threadNum);
}

asyncOpsAreDone.WaitOne();
Console.WriteLine("All operations have completed.");
}


// The callback method's signature MUST match that of a System.Threading.TimerCallback
// delegate (it takes an Object parameter and returns void)
static void UpdateResource(Object state) {
res.Access((Int32) state);
if (Interlocked.Decrement(ref numAsyncOps) == 0)
asyncOpsAreDone.Set();
}
}
VS自己带的例子,