Programming Reactive Extensions and LINQ

ReactiveCommand

ReactiveCommand is an ICommand implementation that is simultaneously a simple ICommand implementation and some extra bits that are pretty motivating. First, we can treat this as a non-Rx enabled ICommand, using the Create static method, as follows:

var cmd = ReactiveCommand.Create(x => true, x => Console.WriteLine(x)); cmd.CanExecute(null); >> true cmd.Execute("Hello"); >> "Hello"

Here's where it gets interesting—we can also provide IObservable as our CanExecute. For example, the following is a command that can only run when the mouse is up:

var mouseIsUp = Observable.Merge(     Observable.FromEvent<MouseButtonEventArgs>(window, "MouseDown").Select(_ => false),     Observable.FromEvent<MouseButtonEventArgs>(window, "MouseUp").Select(_ ...