Change notifications and watching

TagBites.IO exposes two different mechanisms for reacting to changes - pick the one that matches what you actually need to observe.

FileSystem events

Every FileSystem instance raises Creating/Created, Changing/Changed, Deleting/Deleted and Moving/Moved events whenever an operation is performed through that instance, regardless of the underlying provider:

var fileSystem = FileSystem.Local;
fileSystem.Created += (sender, e) => Console.WriteLine($"Created: {e.Link.FullName}");
fileSystem.Changed += (sender, e) => Console.WriteLine($"Changed: {e.Link.FullName}");
fileSystem.Deleted += (sender, e) => Console.WriteLine($"Deleted: {e.Link.FullName}");
fileSystem.Moved += (sender, e) => Console.WriteLine($"Moved: {e.Link.FullName} -> {e.Destination.FullName}");

fileSystem.GetFile("file.txt").WriteAllText("content"); // raises Creating/Created

These events only fire for operations your own code performs via this FileSystem object - they are not a substitute for watching for changes made by other processes or users.

Watchers

DirectoryLink.CreateWatcher(recursive) and FileSystemStructureLink.CreateWatcher() return an IFileSystemLinkWatcher with its own Created/Changed/Deleted/Moved events:

var directory = FileSystem.Local.GetDirectory("C:/Files");
using var watcher = directory.CreateWatcher(recursive: true);
watcher.Changed += (sender, e) => Console.WriteLine($"Changed: {e.Link.FullName}");

Important: only FileSystem.Local and the virtual file system implement real, OS-level watching that detects changes made by other processes. Every other built-in provider (FTP, SFTP, HTTP, ZIP, Dropbox, Google Cloud Storage, S3) falls back to a watcher that only reacts to changes made through the same FileSystem instance in the current process - it will not notice a file someone else uploads directly to the server. If you need to detect changes made outside your process against a remote storage, poll it instead (e.g. periodically re-list the directory, or call FileSystemLinkSynchronizer.ForceSyncAsync() - see synchronization).