傳統機台也可以 IoT：使用 FileSystemWatcher 監看檔案或資料夾變化

    public static void Run()
    {
        // 建立一個 FileSystemWatcher 實體，並設定相關屬性
        var watcher = new FileSystemWatcher
        {
            // 設定要監看的資料夾
            Path = "C:\MonitoringFolder",
            // 設定要監看的變更類型，這裡設定監看最後修改時間與修改檔名的變更事件
            NotifyFilter = NotifyFilters.LastWrite | NotifyFilters.FileName,
            // 設定要監看的檔案類型
            Filter = "*.CSV",
            // 設定是否監看子資料夾
            IncludeSubdirectories = false,
            // 設定是否啟動元件，必須要設定為 true，否則監看事件是不會被觸發
            EnableRaisingEvents = true
        };

        // 設定監看事件對應的處理邏輯
        watcher.Changed += new FileSystemEventHandler(OnChanged);
        watcher.Created += new FileSystemEventHandler(OnChanged);
        watcher.Deleted += new FileSystemEventHandler(OnChanged);
        watcher.Renamed += new RenamedEventHandler(OnRenamed);

        Console.ReadLine();
    }

    // 定義處理邏輯
    private static void OnChanged(object source, FileSystemEventArgs e)
    {
       Console.WriteLine("檔案變更: " +  e.FullPath + " " + e.ChangeType);
    }

    private static void OnRenamed(object source, RenamedEventArgs e)
    {
        Console.WriteLine("檔名變更: {0} 重新命名為 {1}", e.OldFullPath, e.FullPath);
    }

private static void AppendTextSimulator(string filePah)
{
    var rand = new Random();
    var date = DateTime.Now;
    for (var i = 0; i < 1000; i++)
    {
        Thread.Sleep(rand.Next(1000, 1200));
        using (var sw = File.AppendText(filePah))
        {
            sw.WriteLine($@"{i},{date.ToShortDateString()},{rand.Next(1, 10)},{rand.Next(50, 100)},{(float)rand.Next(1, 10) / 10}");
        }
    }
}

public class Watcher
{
    private readonly FileSystemWatcher _watch;
    public Watcher(string watchFolder)
    {
        _watch = new FileSystemWatcher
        {
            // 設定要監看的資料夾
            Path = watchFolder,
            // 設定要監看的變更類型
            NotifyFilter = NotifyFilters.LastWrite | NotifyFilters.FileName | NotifyFilters.DirectoryName,
            // 設定要監看的檔案類型
            Filter = "*.CSV",
            // 設定是否監看子資料夾
            IncludeSubdirectories = false,
            // 設定是否啟動元件，必須要設定為 true，否則事件是不會被觸發
            EnableRaisingEvents = true
        };
    }
    /// <summary>
    /// 設定監看新增檔案的觸發事件
    /// </summary>
    public Watcher WatchCreated()
    {
        _watch.Created += new FileSystemEventHandler(_Watch_Created);
        return this;
    }
    /// <summary>
    /// 設定監看修改檔案的觸發事件
    /// </summary>
    public Watcher WatchChanged()
    {
        _watch.Changed += new FileSystemEventHandler(_Watch_Changed);
        return this;
    }
    /// <summary>
    /// 設定監看重新命名的觸發事件
    /// </summary>
    public Watcher WatchRenamed()
    {
        _watch.Renamed += new RenamedEventHandler(_Watch_Renamed);
        return this;
    }
    /// <summary>
    /// 設定監看刪除檔案的觸發事件
    /// </summary>
    public Watcher WatchDeleted()
    {
        _watch.Deleted += new FileSystemEventHandler(_Watch_Deleted);
        return this;
    }
    /// <summary>
    /// 當所監看的資料夾有建立文字檔時觸發
    /// </summary>
    private static void _Watch_Created(object sender, FileSystemEventArgs e)
    {
        var sb = new StringBuilder();
        var dirInfo = new DirectoryInfo(e.FullPath);
        sb.AppendLine($"新建檔案於：{dirInfo.FullName.Replace(dirInfo.Name, "")}");
        sb.AppendLine($"新建檔案名稱：{dirInfo.Name}");
        sb.AppendLine($"建立時間：{dirInfo.CreationTime}");
        sb.AppendLine($"目錄下共有：{dirInfo.Parent?.GetFiles().Length} 檔案");
        sb.AppendLine($"目錄下共有：{dirInfo.Parent?.GetDirectories().Length} 資料夾");
        Console.WriteLine(sb.ToString());
    }
    /// <summary>
    /// 當所監看的資料夾有文字檔檔案內容有異動時觸發
    /// </summary>
    private static void _Watch_Changed(object sender, FileSystemEventArgs e)
    {
        var sb = new StringBuilder();
        var dirInfo = new DirectoryInfo(e.FullPath);
        sb.AppendLine($"被異動的檔名為：{e.Name}");
        sb.AppendLine($"檔案所在位址為：{e.FullPath.Replace(e.Name, "")}");
        sb.AppendLine($"異動內容時間為：{dirInfo.LastWriteTime}");
        sb.AppendLine($"最後一筆內容：{File.ReadLines(e.FullPath).Last()}");
        Console.WriteLine(sb.ToString());
    }
    /// <summary>
    /// 當所監看的資料夾有文字檔檔案重新命名時觸發
    /// </summary>
    private static void _Watch_Renamed(object sender, RenamedEventArgs e)
    {
        var sb = new StringBuilder();
        var fileInfo = new FileInfo(e.FullPath);
        sb.AppendLine($"檔名更新前：{e.OldName}");
        sb.AppendLine($"檔名更新後：{e.Name}");
        sb.AppendLine($"檔名更新前路徑：{e.OldFullPath}");
        sb.AppendLine($"檔名更新後路徑：{e.FullPath}");
        sb.AppendLine($"建立時間：{fileInfo.LastAccessTime}");
        Console.WriteLine(sb.ToString());
    }

    /// <summary>
    /// 當所監看的資料夾有文字檔檔案有被刪除時觸發
    /// </summary>
    private static void _Watch_Deleted(object sender, FileSystemEventArgs e)
    {
        var sb = new StringBuilder();
        sb.AppendLine($"被刪除的檔名為：{e.Name}");
        sb.AppendLine($"檔案所在位址為：{e.FullPath.Replace(e.Name, "")}");
        sb.AppendLine($"刪除時間：{DateTime.Now}");
        Console.WriteLine(sb.ToString());
    }
}

static void Main(string[] args)
{
    var monitoringPath = @"C:\TestFileWatcher\";
    Console.WriteLine("Monitoring file changed in target folder.");
    Console.WriteLine($"Target Folder: {monitoringPath}");

    // 透過鏈接的技巧可以一路用 . 的方式來加入要監看的事件
    new Watcher(monitoringPath)
        .WatchCreated()
        .WatchChanged();

    Console.ReadLine();
}