How to migrate from ReactiveUI 4.x

Moving to ReactiveUI 5.0 is usually straightforward, but there are a few things to know.

Changes that may be more difficult to deal with

  • ReactiveUI 5.0 is .NET 4.5 only - this means that Silverlight 5, .NET 4.0, and WP7.x are all unsupported. If you want to use ReactiveUI with these platforms, you have to stay on the 4.x series. You can do this by changing the lines in your "packages.config" to always use the latest version from the 4.x series:

xml <package id="reactiveui-core" version="(4.0.0, 5.0.0)" />

  • ReactiveCommand now does not have an imperative constructor (i.e. ReactiveCommand.Create). This constructor is something that you probably shouldn't be using anyways, but if you really need it, you can find the original ReactiveCommand in the ReactiveUI.Legacy namespace.

  • ReactiveUI now uses a much more simplified Service Location (i.e. IoC without injection) model than RxUI 4.x. However, this new interface (IMutableDependencyResolver) is not always straightforward to implement with existing IoC containers. The method RxApp.InitializeCustomResolver as well as the FuncDependencyResolver can be used during IoC setup to help you out. If you never used a custom IoC container, then you don't have to do anything here, It Just Works™.

  • Validation has been removed, this will be re-added in a future release. If you need this, grab the old version of the class from here

Changes that are pretty easy to deal with

  • ReactiveCollection is now ReactiveList

  • Many things that were in ReactiveUI.Xaml are now in ReactiveUI

  • The ReactiveUI.Routing namespace is gone, it has been moved into ReactiveUI and ReactiveUI.{Cocoa/Xaml/Android} - in general, the "Platform" DLLs are now much smaller and only contain platform-specific controls.

  • ReactiveAsyncCommand and ReactiveCommand are now the same class, and some of the async registration methods have changed.

  • MakeObjectReactiveHelper is removed, because you don't need it anymore, RxUI will Just Work™ without it. Just remove the boilerplate code if you were using it.

  • The old syntax for declaring read-write properties is now removed, the only correct way to declare properties is now:

cs int foo; public int Foo { get { return foo; } set { this.RaiseAndSetIfChanged(ref foo, value); } }

  • ToProperty no longer sets the ObservableAsPropertyHelper variable via reflection - instead, it is set via an out property.

  • RxApp.DeferredScheduler is now called RxApp.MainThreadScheduler

  • Many old "for compatibility only" methods have now been removed - there is no functionality loss