时间：2019-03-08 标签：c#filesystemwatcher and backgroundworker

Question

我想要同步我的文件夹，所以我有 10 个 Filesystemwatcher 和 4 个 Backgroundworker。这个想法是，一个观察者可以调用 4 个工作人员中的每一个，但我希望观察者选择一个活跃且空闲的工作人员，不应触发其他工作人员。

Exp: 工人 1 被解雇，2-4 没有。

我做错了什么？

这是我的代码

        private void watcher1_OnChanged(object source, FileSystemEventArgs e)
        {
            // File Name
            string file = e.FullPath;

            // refresh App.Config
            ConfigurationManager.RefreshSection("appSettings");

            // Check Worker Active
            bool worker1Active = Convert.ToBoolean(ConfigurationManager.AppSettings["worker1Active"]);
            bool worker2Active = Convert.ToBoolean(ConfigurationManager.AppSettings["worker2Active"]);
            bool worker3Active = Convert.ToBoolean(ConfigurationManager.AppSettings["worker3Active"]);
            bool worker4Active = Convert.ToBoolean(ConfigurationManager.AppSettings["worker4Active"]);

            // Watcher Nummer
            string watcherNr = "Watcher 1";

            // Arguments to call worker
            List<object> arguments = new List<object>();
            arguments.Add(file);
            arguments.Add(watcher1_destinationPath);
            arguments.Add(watcher1_sourcePath);
            arguments.Add(watcherNr);

            bool success = false;

            while (!success == true)
            {
                try
                {
                    using (Stream stream = new FileStream(file, FileMode.Open))
                    {

                            if (worker1Active == true && worker1.IsBusy != true)
                            {
                                worker1.RunWorkerAsync(arguments);
                                success = true;
                                break;
                            }

                            if (worker2Active == true && worker2.IsBusy != true)
                            {
                                worker2.RunWorkerAsync(arguments);
                                success = true;
                                break;
                            }

                            if (worker3Active == true && worker3.IsBusy != true)
                            {
                                worker3.RunWorkerAsync(arguments);
                                success = true;
                                break;
                            }

                            if (worker4Active == true && worker4.IsBusy != true)
                            {
                                worker4.RunWorkerAsync(arguments);
                                success = true;
                                break;
                            }
                    }
                }
                catch
                {
                    success = false;
                }
            }
        }

Answer 1

你应该使用线程池。这将使您的代码看起来更干净，这就是您应该使用的线程机制。它会将任务放在空闲线程之一上，如果所有线程都忙，那么它将等待其中一个线程空闲。

这里是关于如何在 c# 中使用线程池的link。

https://msdn.microsoft.com/en-us/library/3dasc8as(v=vs.80).aspx https://www.dotnetperls.com/threadpool

此外，如果您想继续一次只使用四个线程，您可以设置最大数量。线程中的线程 Here is how to do it.

Answer 2

编辑： 确保在处理期间锁定文件并在处理前检查锁定。如果您有多个工作人员处理一个文件，您将运行遇到问题。只要确保在要处理的文件被锁定时重新排队作业即可。它会自动重新排队，直到解锁。当然你需要注意再次解锁。

这是一个使用线程池的示例应用： ThreadPool 是线程安全的，这意味着当它工作时，它在不同的线程中进行，这将使您的 UI 保持响应而不是阻塞。

玩得开心！

using System;
using System.IO;
using System.Threading;

namespace FileWatcherThreadApp
{
    class Program
    {

        static void Main(string[] args)
        {
            FileSystemWatcher fileWatcher = new FileSystemWatcher(@"C:\Users\BertSinnema\watch");

            //Enable events
            fileWatcher.EnableRaisingEvents = true;

            //Add event watcher
            fileWatcher.Changed += FileWatcher_Changed;
            fileWatcher.Created += FileWatcher_Changed;
            fileWatcher.Deleted += FileWatcher_Changed;
            fileWatcher.Renamed += FileWatcher_Changed;

            var maxThreads = 4;

            // Times to as most machines have double the logic processers as cores
            ThreadPool.SetMaxThreads(maxThreads, maxThreads * 2);


            Console.WriteLine("Listening");
            Console.ReadLine();

        }

        //This event adds the work to the Thread queue
        private static void FileWatcher_Changed(object sender, FileSystemEventArgs e)
        {
            ThreadPool.QueueUserWorkItem((o) => ProcessFile(e));
        }

        //This method processes your file, you can do your sync here
        private static void ProcessFile(FileSystemEventArgs e)
        {
            // Based on the eventtype you do your operation
            switch (e.ChangeType)
            {
                case WatcherChangeTypes.Changed:
                    Console.WriteLine($"File is changed: {e.Name}");
                    break;
                case WatcherChangeTypes.Created:
                    Console.WriteLine($"File is created: {e.Name}");
                    break;
                case WatcherChangeTypes.Deleted:
                    Console.WriteLine($"File is deleted: {e.Name}");
                    break;
                case WatcherChangeTypes.Renamed:
                    Console.WriteLine($"File is renamed: {e.Name}");
                    break;
            }
        }
    }


}

如果您想查看多个文件夹，只需添加另一个 FileSystemWatcher 并将创建、重命名、更改和删除事件挂接到同一个事件处理程序 (FileWatcher_Changed)

时间：2019-03-08 标签：c#filesystemwatcher and backgroundworker

c# filesystemwatcher and backgroundworker

c#

backgroundworker

filesystemwatcher