当目录（FileWatcher）发生变化时如何输出警报消息？答案

【问题标题】：How to output an alert message when something changes in the directory (FileWatcher)?当目录（FileWatcher）发生变化时如何输出警报消息？
【发布时间】：2019-07-25 21:50:18
【问题描述】：

我制作了一个 FileWatcher 来控制特定（路径）目录中是否发生了某些事情。现在，如果发生某些事情，我想在 JavaScript 文件中输出带有创建或重命名的文件名的警报消息。但我不知道如何解决这个问题。

如何使用 HomeController 中的方法在 JavaScript 中获取文件名？还是我必须做一个新的方法？

//FileWatcher.cs
public class FileWatcherService
    {
        public event EventHandler<string> FileCreated;
        public event EventHandler<string> FileDeleted;
        public event EventHandler<RenamedEventArgs> FileRenamed;

        public FileWatcherService()
        {
            FileSystemWatcher fileWatcher = new FileSystemWatcher();

            string path = @"C:\Users\Kopuz\Desktop\Log-Dateien\";
            fileWatcher.Path = path;

            fileWatcher.NotifyFilter = NotifyFilters.LastAccess
                | NotifyFilters.LastWrite
                | NotifyFilters.FileName
                | NotifyFilters.DirectoryName
                | NotifyFilters.CreationTime;

            fileWatcher.Deleted += OnDeleted;
            fileWatcher.Created += OnCreated;
            fileWatcher.Renamed += OnRenamed;

            fileWatcher.EnableRaisingEvents = true;
        }

        private void OnCreated(object sender, FileSystemEventArgs e)
        {
            Console.WriteLine($"File: {e.Name} created on {e.FullPath}");
            FileCreated.Invoke(this, e.FullPath);
        }

        private void OnDeleted(object sender, FileSystemEventArgs e)
        {
            Console.WriteLine($"File: {e.Name} deleted from {e.FullPath}");
            FileDeleted?.Invoke(this, e.FullPath);
        }

        private void OnRenamed(object sender, RenamedEventArgs e)
        {
            Console.WriteLine($"File: {e.OldName} renamed to {e.Name}");
            FileRenamed?.Invoke(this, e);
        }
    }

//HomeController.cs
public HomeController(PerformanceAnalyseToolContext db, FileWatcherService fws)
        {
            this.db = db;
            fws.FileRenamed += FileWatcherService_FileRenamed;
            fws.FileCreated += FileWatcherService_FileCreated;
            fws.FileDeleted += FileWatcherService_FileDeleted;
        }

        private void FileWatcherService_FileDeleted(object sender, string fullPath)
        {
            Console.WriteLine($"HomeController::File deleted: {fullPath}");
        }

        private void FileWatcherService_FileCreated(object sender, string fullPath)
        {
            Console.WriteLine($"HomeController::File created: {fullPath}");

            string fileName = new FileInfo(fullPath).Name;
            Console.WriteLine(fileName);
        }

        private void FileWatcherService_FileRenamed(object sender, RenamedEventArgs e)
        {
            Console.WriteLine($"HomeController::File renamed: {e.OldFullPath} --> {e.FullPath}");

            string fileName = new FileInfo(e.FullPath).Name;
            Console.WriteLine(fileName);
        }

【问题讨论】：

控制器的寿命很短，不能用于消费事件。您可以创建一个后台工作程序来订阅 FileWatcherService 以获取文件事件并跟踪更改，然后控制器可以查看更改。

标签： javascript c# file-watcher

【解决方案1】：

你必须做任何一个投票，这通常是不受欢迎的。

或 websocket 类型的交易，用于此类始终连接推送的双向通信。 https://blog.stanko.io/do-you-really-need-websockets-343aed40aa9b

实时推送更新是 websocket 的用途。

【讨论】：