作为等同于Java的wait,notify,notifyAll的存在,AutoResetEvent和ManualResetEvent分别实现了notify和notifyAll的功能,下面的代码简单讲解了一下实现原理,并展示了这一过程。
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
namespace ThreadTest
{
class Program
{
//新建一个默认无信号的手动重置线程事件
private void Test()
{
ManualResetEvent manualResetEvent = new ManualResetEvent(false);
AutoResetEvent autoResetEvent = new AutoResetEvent(false);
//线程传参需要通过ParameterizedThreadStart委托,并在Start时附加参数。
new Thread(new ParameterizedThreadStart(MyThreadHandler)).Start(new ParamStruct("Thread1", manualResetEvent));
new Thread(new ParameterizedThreadStart(MyThreadHandler)).Start(new ParamStruct("Thread2", manualResetEvent));
new Thread(new ParameterizedThreadStart(MyThreadHandler)).Start(new ParamStruct("Thread3", autoResetEvent));
new Thread(new ParameterizedThreadStart(MyThreadHandler)).Start(new ParamStruct("Thread4", autoResetEvent));
Thread.Sleep(1000);
//manualResetEvent在Set方法中,会让信号状态从无到有,从而让所有wait状态的线程唤醒,实现NotifyAll
manualResetEvent.Set();
//autoResetEvent在Set方法中,会在第一个处于wait状态的线程唤醒后将信号状态Reset,变为无信号,实现NotifyOne
autoResetEvent.Set();
Thread.Sleep(1000);
autoResetEvent.Set();
Console.ReadKey();
}
static void Main(string[] args)
{
new Program().Test();
}
private void MyThreadHandler(object obj)
{
if (obj is ParamStruct paramStruct)
{
Console.WriteLine(paramStruct.threadName);
paramStruct.resetEvent.WaitOne();
Console.WriteLine(paramStruct.threadName + " finished on " + DateTime.Now);
}
}
}
class ParamStruct
{
public string threadName;
public EventWaitHandle resetEvent;
public ParamStruct(string threadName, EventWaitHandle resetEvent)
{
this.threadName = threadName;
this.resetEvent = resetEvent;
}
}
}