c# - 将 System.Threading.Timer 对象引用传递给它的回调函数

Question

是否可以将 System.Threading.Timer 对象引用传递给它的回调函数，如下所示:

System.Threading.Timer myTimer = new System.Threading.Timer(new TimerCallback(DoSomething), myTimer, 2000, Timeout.Infinite);

因为在“DoSomething”方法中我想调用:

myTimer.Change(5000, Timeout.Infinite);

我将在下面粘贴控制台应用程序草稿。想法是这样的:我有计时器列表。每个计时器都会发出一些请求，当它收到请求时，它会更改一些共享数据。但是，我不能将对计时器的引用传递给它的回调，也不能使用它的索引，因为由于某种原因(调查)它变成了“-1”。

using System;
using System.Collections.Generic;
using System.Threading;

namespace TimersInThreads
{
    class Program
    {
        public static int sharedDataInt;
        static private readonly object lockObject = new object();
        public static List<System.Threading.Timer> timers = new List<Timer>();

        static void Main(string[] args)
        {
            System.Threading.Timer timer = new System.Threading.Timer(new TimerCallback(DoSomething), timers.Count - 1, 2000, Timeout.Infinite);
            timers.Add(timer);

            System.Threading.Timer timer2 = new System.Threading.Timer(new TimerCallback(DoSomething), timers.Count - 1, 2000, Timeout.Infinite);
            timers.Add(timer2);

            System.Threading.Timer timer3 = new System.Threading.Timer(new TimerCallback(DoSomething), timers.Count - 1, 2000, Timeout.Infinite);
            timers.Add(timer3);

            //timer = new System.Threading.Timer(new TimerCallback(DoSomething), "Timer 1", 1000, Timeout.Infinite);
            //timer = new System.Threading.Timer(new TimerCallback(DoSomething), "Timer 2", 450, Timeout.Infinite);
            //timer = new System.Threading.Timer(new TimerCallback(DoSomething), "Timer 3", 1500, Timeout.Infinite);

            Console.ReadLine();

        }

        static void DoSomething(object timerIndex)
        {
            // Request
            // Get Response
            var x = getSomeNumberWithDelay();


            // Executes after Response is received
            lock (lockObject)
            {
                sharedDataInt++;
                Console.WriteLine("Timer" + (int)timerIndex + ", SHaredDataInt: " + sharedDataInt + "\t\t" + DateTime.Now.ToString("HH:mm:ss tt") + "." + DateTime.Now.Millisecond.ToString());
            }

            timers[(int)timerIndex].Change(5000, Timeout.Infinite);
        }

        static int getSomeNumberWithDelay()
        {
            Thread.Sleep(5000);
            return 3;
        }
    }
}

请给我一些想法或建议。非常感谢，谢谢!

Answer 1

Timer constructor 中的state 参数作为参数传递给 TimerCallback - 这只是一个 object 因此可以处理任何东西，包括计时器引用本身。

所以

new System.Threading.Timer(new TimerCallback(DoSomething), myTimer, 2000, Timeout.Infinite);

是完全可以接受的。在您的回调中，您只需要将参数转换为 Timer 例如

static void DoSomething(object state)
{
    ...
    var timer = (System.Threading.Timer)state;
}

---

再看看你的问题，我明白你想做的是将计时器作为参数传递给它的构造函数(这显然不能完成，因为它还没有正式声明然而)。您可以通过将计时器显式传递给回调来解决此问题，例如

Timer t = null;
t = new Timer(delegate { DoSomething(t); }, null, 2000, Timeout.Infinite);

当触发回调时，t 将设置为计时器的引用。