public static class ReactiveNavigationObserves a NavigationRegion and goes back with a ReactiveUI command. The navigator replaces ReactiveUI's RoutingState; these helpers do not wrap one.
Remarks
Each subscription receives its initial value on the subscribing thread, inside Subscribe. Later values arrive on the model turn in which the region raises the change; content changes arrive on the navigation's commit turn. Use ObserveOn to move to another scheduler. An entry's lifetime is not ReactiveUI activation: a retained entry stays alive while it is not presented, and its View may deactivate and activate again when it returns.
Methods
CreateBackCommand
public static ReactiveCommand<RxVoid, NavigationResult<TContent>> CreateBackCommand<TContent>(this NavigationRegion<TContent> region, ISequencer scheduler) where TContent : classCreates a command that goes back in region. It can execute while NavigationRegion.CanGoBack is true and NavigationRegion.IsTransitioning is false, and its output is the NavigationResult. CanExecute reflects this region only: a transition of an ancestor region does not disable it.
Parameters
regionThe region.
schedulerThe scheduler of the command's output and
CanExecute, such as the model context's scheduler fromIRunicReactiveSchedulerProvider.
Remarks
A rejected, superseded or failed Back is a result, not an exception, so ThrownExceptions reports only defects and cancellation. Subscribe to the command's ThrownExceptions; without a subscriber ReactiveUI routes them to its default exception handler. Apps that use Runic Views can use RunicReactiveExceptions.ObserveBridgeExceptions from Runic.Application.ReactiveUI. Overlapping executions to the same destination share one Back and confirmation. Cancelling one execution cancels that caller; the shared Back is cancelled only when every caller cancels before commit. The command observes the region through a PropertyChanged handler until the command is disposed, so dispose it with its owner, for example with DisposeWith.
WhenCanGoBackChanged
public static IObservable<bool> WhenCanGoBackChanged<TContent>(this NavigationRegion<TContent> region) where TContent : classObserves whether the region has Back history. Each subscription receives the current value and then each different value. This does not include transition availability; compose with ReactiveNavigation.WhenIsTransitioningChanged when creating a command.
Remarks
The sequence never completes; dispose the subscription to stop observing.
WhenCurrentChanged
public static IObservable<TContent?> WhenCurrentChanged<TContent>(this NavigationRegion<TContent> region) where TContent : classObserves the region's NavigationRegion.Current content. Each subscription receives the current value, or null when the region is empty, and then each different instance. Pushing the same borrowed instance again does not emit; observe ReactiveNavigation.WhenEntryChanged to see every entry.
Remarks
The sequence never completes; dispose the subscription to stop observing.
WhenEntryChanged
public static IObservable<NavigationEntry<TContent>?> WhenEntryChanged<TContent>(this NavigationRegion<TContent> region) where TContent : classObserves the region's NavigationRegion.CurrentEntry. Each subscription receives the current entry, or null when the region is empty, and then each different entry, also when two entries present the same content.
Remarks
The sequence never completes; dispose the subscription to stop observing.
WhenIsTransitioningChanged
public static IObservable<bool> WhenIsTransitioningChanged<TContent>(this NavigationRegion<TContent> region) where TContent : classObserves whether the region has an unsettled transition, including operations started by other callers. Each subscription receives the current value and then each different value observed when the region raises a change. An ancestor's transitions are not included.
Remarks
The sequence never completes; dispose the subscription to stop observing.