Modified event of FileSystemWatcher getting triggered multiple times [duplicate]

问题

I want to monitor the following

New File being created/copied to the directory
Existing file edited

I use the following code to subscribe to the created and changed event of the FileSystemWatcher class.I have noted some issues with FSW Class.

On replacing files, the changed event is getting triggered numerous times.

How can i get over this issue.Kindly advice.

 watcher.Path = watchpath;
 watcher.Filter = "*.*";
 watcher.Created += new FileSystemEventHandler(copied);
 watcher.Changed += new FileSystemEventHandler(Watcher_Changed);
 watcher.NotifyFilter = NotifyFilters.LastWrite;
 watcher.EnableRaisingEvents = true;

For a single item copied to the folder,the following events are raised

  *******> Created 
    -----> Changed 
    -----> Changed

回答1:

Yes, that is expected as already mentioned in the comments. Also have a look at : FileSystemWatcher Changed event is raised twice

to have a workaround you will need to add a dictionary which will track the raised events for every files.

Dictionary<string, DateTime> lastWriteDate //fileName - Last write date time

and in changed event you will have to handle it like below,

    private static void Watcher_Changed(object sender, System.IO.FileSystemEventArgs e)
    {
        string filePath = e.FullPath;
        DateTime writeDate = System.IO.File.GetLastWriteTime(filePath);
        if (lastWriteDate.ContainsKey(filePath))
        {
            if (lastWriteDate[filePath] == writeDate) 
                //Exit as we already have raised an event for this
                return;
            lastWriteDate[filePath] = writeDate;
        }
        else
        {
            lastWriteDate.Add(filePath, writeDate);
        }

        //Do your stuff.
    }

来源：https://stackoverflow.com/questions/55015132/modified-event-of-filesystemwatcher-getting-triggered-multiple-times

标签

.net

filesystemwatcher