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Windows Forms

Run the complete page example.

Warning

ReactiveUI drops a target framework after Microsoft ends support for it. .NET 8 and .NET 9 reach end of support on November 10, 2026, and .NET Framework 4.6.2 reaches end of support on January 12, 2027. Plan to move new and existing apps to .NET 10 or later, or to .NET Framework 4.7.2 or later.

Add ReactiveUI.WinForms to your Windows Forms application project. It brings ReactiveUI and, through it, ReactiveUI.Binding.

dotnet add package ReactiveUI.WinForms

ReactiveUI.WinForms also ships as ReactiveUI.WinForms.Reactive, built from the same source, for an app that uses System.Reactive.

Configure ReactiveUI at startup

Call WithWinForms on the app builder once, in Main, before you run your first form. WithWinFormsScheduler sets only the WinForms main-thread sequencer, for an app that registers the platform module another way.

IReactiveUIBuilder builder = RxAppBuilder.CreateReactiveUIBuilder()
    .WithWinForms()
    .WithWinFormsScheduler();

_ = builder.BuildApp();

WithWinForms registers the WinForms platform module, its activation fetcher and its main-thread sequencer. RxAppBuilder covers the builder itself, and Windows Forms covers everything you build with the package: a Form or UserControl that implements IViewFor<TViewModel>, RoutedControlHost and ViewModelControlHost for showing a router's current page or previewing a view model, and binding with Bind, OneWayBind and BindCommand.

The compelling example walks through a first view model and view. There is no ReactiveUI.Validation code in this installation's example project; see Validation for validation rules on a view model.