The code:
public class AppViewModel : ReactiveObject { public AppViewModel() { Observable.Timer(TimeSpan.FromSeconds(1), TimeSpan.FromSeconds(1), RxApp.MainThreadScheduler) .Do(_ => Score++) .Subscribe(); } private long _score; public long Score { get => _score; set => this.RaiseAndSetIfChanged(ref _score, value); } } Is functionally equivalent to:
public class AppViewModel : ReactiveObject { private readonly ObservableAsPropertyHelper<long> _score; public AppViewModel() { _score = Observable .Timer(TimeSpan.FromSeconds(1), TimeSpan.FromSeconds(1), RxApp.MainThreadScheduler) .ToProperty(this, x => x.Score); } public long Score => _score.Value; } Although, in the second case, there's a noticeable delay (of over a second on my machine) before counting starts. What would be the cause of this?
For completeness:
MainWindow.xaml
<reactiveui:ReactiveWindow x:Class="ReactiveDemo.MainWindow" x:TypeArguments="reactivedemo:AppViewModel" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:reactivedemo="clr-namespace:ReactiveDemo" xmlns:reactiveui="http://reactiveui.net" Title="Rx" Height="450" Width="800" mc:Ignorable="d"> <Viewbox> <Label x:Name="ScoreLabel" ContentStringFormat="D2" FontFamily="Lucida Console" /> </Viewbox> </reactiveui:ReactiveWindow> MainWindow.xaml.cs
using ReactiveUI; using System.Reactive.Disposables; namespace ReactiveDemo { public partial class MainWindow : ReactiveWindow<AppViewModel> { public MainWindow() { InitializeComponent(); ViewModel = new AppViewModel(); this.WhenActivated(disposableRegistration => { this.OneWayBind(ViewModel, viewModel => viewModel.Score, view => view.ScoreLabel.Content) .DisposeWith(disposableRegistration); }); } } } 
