public MainWindowViewModel() { MainText.AddTo(Disposable); LowerText = MainText .Select(x => ConvertLower(x)) .ToReadOnlyReactivePropertySlim() .AddTo(Disposable); TextCount = MainText .Select(s => s.Length) .ToReadOnlyReactivePropertySlim() .AddTo(Disposable); Now = Observable.Interval(TimeSpan.FromSeconds(1)) .Select(_ => DateTime.Now) .ToReadOnlyReactivePropertySlim(DateTime.Now) .AddTo(Disposable); }