c# - 用于文件列表的 FileSystemwatcher

Question

我一直在关注这里的指导 FileSystemWatcher Changed event is raised twice .

但是我有一个我正在观看的文件列表，所以如果我一起删除 20 个文件，事件将被调用 20 次。这是预期的并且工作正常。

我怎样才能为 20 个“同时”文件更改只触发一次事件(即我怎样才能忽略所有其他文件更改，直到下面 Onchanged 的第一个实例中的代码完成。正确的现在 Onchanged 被调用了 20 次。) ?

private void Main_Load(object sender, EventArgs e)
{
    public static List<FileSystemWatcher> watchers = new List<FileSystemWatcher>();
    UpdateWatcher();
}


public void OnChanged(object sender, FileSystemEventArgs e)
{
    try
    {
      Logging.Write_To_Log_File("Item change detected " + e.ChangeType + " " + e.FullPath + " " + e.Name, MethodBase.GetCurrentMethod().Name, "", "", "", "", "", "", 2);
      watchers.Clear();

      foreach (FileSystemWatcher element in MyGlobals.watchers)
      {
        element.EnableRaisingEvents = false;
      }

      //Do some processing on my list of files here....
      return;

    }    
    catch (Exception ex)
    {
       // If exception happens, it will be returned here
    }                
    finally
    {
         foreach (FileSystemWatcher element in MyGlobals.watchers)
         {
            element.EnableRaisingEvents = true;
         }
    }
}





public void UpdateWatcher() // Check Items
        {

        try
        {
        watchers.Clear();

        for (int i = 0; i < MyGlobals.ListOfItemsToControl.Count; i++) // Loop through List with for
        {
        FileSystemWatcher w = new FileSystemWatcher();
         w.Path = Path.GetDirectoryName(MyGlobals.ListOfItemsToControl[i].sItemName); // File path    
        w.Filter = Path.GetFileName(MyGlobals.ListOfItemsToControl[i].sItemName); // File name
        w.Changed += new FileSystemEventHandler(OnChanged);
        w.Deleted += new FileSystemEventHandler(OnChanged);
        w.Created += new FileSystemEventHandler(OnChanged);
        w.EnableRaisingEvents = true;
        watchers.Add(w);
        }
        }
        catch (Exception ex)
        {
        // If exception happens, it will be returned here

        }
        }

Answer 1

这里的关键点是“在一起”对您意味着什么。毕竟系统对每个都执行独立的删除操作，这在技术上意味着它们不会在同一时间全部删除，但如果你只是想接近，假设它们在彼此相隔 5 秒内全部删除，那么我们只希望 OnChange 触发一次，您可以执行以下操作。请注意，这不会处理重命名更改通知。你没有听它，所以我认为你不需要。

您可能想根据您的使用情况将 5 秒窗口更改为一个小窗口。

    class SlowFileSystemWatcher : FileSystemWatcher
    {
        public delegate void SlowFileSystemWatcherEventHandler(object sender, FileSystemEventArgs args);

        public event SlowFileSystemWatcherEventHandler SlowChanged;
        public DateTime LastFired { get; private set; }

        public SlowFileSystemWatcher(string path)
            : base(path)
        {
            Changed += HandleChange;
            Created += HandleChange;
            Deleted += HandleChange;
            LastFired = DateTime.MinValue;
        }

        private void SlowGeneralChange(object sender, FileSystemEventArgs args)
        {
            if (LastFired.Add(TimeSpan.FromSeconds(5)) < DateTime.UtcNow)
            {
                SlowChanged.Invoke(sender, args);
                LastFired = DateTime.UtcNow;
            }
        }

        private void HandleChange(object sender, FileSystemEventArgs args)
        {
            SlowGeneralChange(sender, args);
        }

        protected override void Dispose(bool disposing)
        {
            SlowChanged = null;
            base.Dispose(disposing);
        }
    }