Using multiple FileSystemWatchers

Question

I want to use multiple FileSystemWatchers to watch different text files.

I am successful in creating the watchers and the file change events are being invoked and I can add the changes in the text files to a string and display this on a form.

What I want to know is how I can tell which watcher is causing the event?

Eg. watcher1, watcher2 or watcher3?

I know I can find out the path and file name of the file that has changed but this doesn't really help me.

Answer 1

I realize you already found your own way to do this, but I recommend you look at the sender parameter within the event that is being fired. This is common for a lot of events. Here is a small example:

private static FileSystemWatcher watcherTxt;
private static FileSystemWatcher watcherXml;

static void Main(string[] args)
{
    String dir = @"C:\temp\";

    watcherTxt = new FileSystemWatcher();
    watcherTxt.Path = dir;
    watcherTxt.Filter = "*.txt";
    watcherTxt.EnableRaisingEvents = true;
    watcherTxt.Created += new FileSystemEventHandler(onCreatedFile);

    watcherXml = new FileSystemWatcher();
    watcherXml.Path = dir;
    watcherXml.Filter = "*.xml";
    watcherXml.EnableRaisingEvents = true;
    watcherXml.Created += new FileSystemEventHandler(onCreatedFile);

    Console.ReadLine();
}

private static void onCreatedFile(object sender, FileSystemEventArgs e)
{
    if (watcherTxt == sender)
    {
        Console.WriteLine("Text Watcher Detected: " + e.FullPath);
    }

    if (watcherXml == sender)
    {
        Console.WriteLine("XML Watcher Detected: " + e.FullPath);
    }
}