ObservableFileSystemWatcher.cs

namespace RxFileSystemWatcher
{
	using System;
	using System.IO;
	using System.Reactive.Linq;

	/// <summary>
	///     This is a wrapper around a file system watcher to use the Rx framework instead of event handlers to handle
	///     notifications of file system changes.
	/// </summary>
	public class ObservableFileSystemWatcher : IDisposable
	{
		public readonly FileSystemWatcher Watcher;

		public IObservable<FileSystemEventArgs> Changed { get; private set; }
		public IObservable<RenamedEventArgs> Renamed { get; private set; }
		public IObservable<FileSystemEventArgs> Deleted { get; private set; }
		public IObservable<ErrorEventArgs> Errors { get; private set; }
		public IObservable<FileSystemEventArgs> Created { get; private set; }

		/// <summary>
		///     Pass an existing FileSystemWatcher instance, this is just for the case where it's not possible to only pass the
		///     configuration, be aware that disposing this wrapper will dispose the FileSystemWatcher instance too.
		/// </summary>
		/// <param name="watcher"></param>
		public ObservableFileSystemWatcher(FileSystemWatcher watcher)
		{
			Watcher = watcher;

			Changed = Observable
				.FromEventPattern<FileSystemEventHandler, FileSystemEventArgs>(h => Watcher.Changed += h, h => Watcher.Changed -= h)
				.Select(x => x.EventArgs);

			Renamed = Observable
				.FromEventPattern<RenamedEventHandler, RenamedEventArgs>(h => Watcher.Renamed += h, h => Watcher.Renamed -= h)
				.Select(x => x.EventArgs);

			Deleted = Observable
				.FromEventPattern<FileSystemEventHandler, FileSystemEventArgs>(h => Watcher.Deleted += h, h => Watcher.Deleted -= h)
				.Select(x => x.EventArgs);

			Errors = Observable
				.FromEventPattern<ErrorEventHandler, ErrorEventArgs>(h => Watcher.Error += h, h => Watcher.Error -= h)
				.Select(x => x.EventArgs);

			Created = Observable
				.FromEventPattern<FileSystemEventHandler, FileSystemEventArgs>(h => Watcher.Created += h, h => Watcher.Created -= h)
				.Select(x => x.EventArgs);
		}

		/// <summary>
		///     Pass a function to configure the FileSystemWatcher as desired, this constructor will manage creating and applying
		///     the configuration.
		/// </summary>
		public ObservableFileSystemWatcher(Action<FileSystemWatcher> configure)
			: this(new FileSystemWatcher())
		{
			configure(Watcher);
		}

		public void Start()
		{
			Watcher.EnableRaisingEvents = true;
		}

		public void Stop()
		{
			Watcher.EnableRaisingEvents = false;
		}

		public void Dispose()
		{
			Watcher.Dispose();
		}
	}
}