ReactiveProperty documentation

# ReactivePropertySlim

ReactivePropertySlim is a lightweight version ReactiveProperty. ReactivePropertySlim is five times faster than ReactiveProperty.

ReactivePropertySlim provides following features:

  • Implements INotifyPropertyChanged interface.
  • Implements IObservable<T> interface.
  • Provides a Value property.
  • Provides a ForceNotify method.

ReactivePropertySlim is high performance. The following table is a result of the benchmark test between ReactiveProperty and ReactivePropertySlim. ReactivePropertySlim is 16 times performance to create an instance, 36 times performance on the primary use case.

|                             Method |         Mean |     Error |    StdDev |
|----------------------------------- |-------------:|----------:|----------:|
|     CreateReactivePropertyInstance |    87.146 ns | 0.8331 ns | 0.7385 ns |
| CreateReactivePropertySlimInstance |     5.460 ns | 0.0537 ns | 0.0502 ns |
|           BasicForReactiveProperty | 2,470.957 ns | 9.1934 ns | 8.1497 ns |
|       BasicForReactivePropertySlim |    68.773 ns | 1.3841 ns | 1.8478 ns |

This class can be used like a ReactiveProperty.

var rp = new ReactivePropertySlim<string>("neuecc");
rp.Select(x => $"{x}-san").Subscribe(x => Console.WriteLine(x));
rp.Value = "xin9le";
rp.Value = "okazuki";

Output is as below.

neuecc-san
xin9le-san
okazuki-san

One difference to ReactiveProperty is that ReactivePropertySlim can't be created from IObservable<T>.

// It isn't valid code.
var rp = Observable.Interval(TimeSpan.FromSeconds(1)).ToReactivePropertySlim();

If you want to create Slim class's instance from IObservable<T>, then use the ToReadOnlyReactivePropertySlim extension method.

var rp = Observable.Interval(TimeSpan.FromSeconds(1)).ToReadOnlyReactivePropertySlim();

# Dispatch to UI thread

ReactivePropertySlim class doesn't dispatch to the UI thread automatically. If you need this, then use the ReactiveProperty or dispatch to the UI thread explicitly.

var rp = Observable.Interval(TimeSpan.FromSeconds(1))
    .ObserveOnUIDispatcher() // dispatch to UI thread
    .ToReadOnlyReactivePropertySlim();

# Validation

ReactivePropertySlim class doesn't provide the validation feature. If you want this feature, then use the ReactiveProperty class.