Question

I´m writing on an service to watch for the existence different files in diffent folders…
I´m using filesystemwatchers to get the events.

As a part of the deployment one of the watched folders is deleted and new created from time to time.

As a result the service throws an error and is stopped…

Is it possible to catch that kind of error and recreate the filewatcher on the new folder by the service?

Answer 1

Catch the deleted event, and then reschedule with timed poll to watch a new one?

I don’t have a compiler to hand right now but I knocked up this pseudo code:

using System;
using System.IO;


    public class Watcher : IDisposable{

    void Dispose(){ watcher.OnDeleted -= onDelete; }


    string file;
    FileSystemWatcher watcher; 
    FileSystemEventHandler onDelete;

        public class Watch(string file, FileSystemEventHandler onDelete) {
        this.file = file;   
        watcher = new FileSystemWatcher{ Path = file }
        this.OnDelete = onDelete;
        watcher.Deleted += onDelete;
        watcher.NotifyFilter = ...; // looking for delete event;
            // Begin watching.
            watcher.EnableRaisingEvents = true;
    }
    }


    public static class watch {

    Watcher watcher;

       public static void Main() {



        watcher = new Watcher("somedir", ondeleted);
        SetUpChangeWatchers();
        while(true){
            // stuff!

        }

        CleanUpChangeWatchers();    
       }    


    private static void ondeleted(object source, RenamedEventArgs e){ 
        CleanUpChangeWatchers();
        watcher.Dispose();

        while(!directoryRecreated(file)){
            Thread.Sleep(...some delay..);
        }
        SetUpChangeWatchers();  
        watcher = new Watcher("somedir", ondeleted);

    }
}