Reactive Extensions Instant Search for WPF/MVVM

Question

I would like to implement a TextBox where, as you type, results appear instantly in another ListBox. I\'ve been looking for examples with Reactive Extensions (Rx), and all o

Answer 1

This is the kind of approach that I would use in this instance:

        var query = Observable.FromEventPattern
            (
                h => textBox1.TextChanged += h,
                h => textBox1.TextChanged -= h)
            .Throttle(TimeSpan.FromMilliseconds(100))
            .ObserveOnDispatcher()
            .Select(x => textBox1.Text)
            .DistinctUntilChanged()
            .Do(x => listBox1.Items.Clear())
            .ObserveOn(Scheduler.Default)
            .Select(x => executeSearch(x))
            .Switch()
            .ObserveOnDispatcher();

        query.Subscribe(x => listBox1.Items.Add(x));

The executeSearch code has the following signature: Func>.

The important part with this query is the final Switch statement. It turns an IObservable> into a IObservable by only returning the results of the latest observable.

The calls to .ObserveOnDispatcher() & .ObserveOn(Scheduler.Default) ensure that different parts of the observable query happen on the correct threads.