初识响应式，Rx.Net

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Reactive.Disposables;
using System.Reactive.Linq;
using System.Threading;
using System.Threading.Tasks;
using System.Windows;

namespace WpfApp1 {
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window {
        public MainWindow() {
            InitializeComponent();
        }

        private void Window_Loaded(object sender, RoutedEventArgs e) {
            this.Async();
        }
        void Sync() {
            for (int i = 0; i < 10; i++) {
                this.tb.Text = i.ToString();
            }
        }
        void Async() {
            var x = from i in AsyncItem2()
                    where i%2==0 select i;
            x.Subscribe(
                i => this.tb.Text = i.ToString(),
                i=>this.tb.Text="xxxxx"
            );            
        }
        async IAsyncEnumerable<int> AsyncItem() {
            for (int i = 0; i < 12; i++) {
                await Task.Delay(1000);
                yield return i;
            }
        }
        IObservable<int> AsyncItem2() {
            var x = Observable.Create<int>(
                async o => {
                    await foreach (var item in AsyncItem()) {
                        o.OnNext(item);
                    }
                    o.OnCompleted();
                    return Disposable.Empty;
                }
            );
            return x;
        }
    }
}