OutWit.Common.MVVM.Navigation.Avalonia 1.0.0

OutWit.Common.MVVM.Navigation.Avalonia

The Avalonia half of OutWit.Common.MVVM.Navigation. Runnable sample: OutWit.Common.MVVM.Navigation.Avalonia.Sample.

• ViewLocator — an IDataTemplate and the core's IViewFactory: the view registry first (the only path under trimming/AOT), then a naming convention searched in the view model's own assembly, so module assemblies are found. Created from DI so views may take dependencies.
• NavigationOutlet — a control that hosts an INavigationOutlet and owns the views: for Cached routes the view of each view model survives navigations (scroll position, column widths, expensive controls), for Transient routes it goes with the view model. Set TransitionDuration to fade between screens; the fade is on the outlet itself, so a cached view is never asked to be in two places at once, and a fade that is overtaken hands over cleanly.
• DialogHostWindow / DialogHostOverlay — IDialogHost implementations without external dependencies: modal windows (nest) or a dimmed overlay on the active window (one at a time).
• IApplicationResources — lets a UI module add its styles and resource dictionaries.
• AddAvaloniaNavigation() — registers all of the above plus AvaloniaDispatcher as IDispatcher.

Setup

// App.axaml.cs, OnFrameworkInitializationCompleted
var services = new ServiceCollection();

services.AddNavigation(nav =>
{
    nav.AddRoute<StudiesViewModel>(Routes.STUDIES);
    nav.AddRoute<StudyViewModel>(Routes.STUDY, NavigationRouteMode.Transient);
});
services.AddAvaloniaNavigation(o => o.UseOverlayDialogs());     // or UseWindowDialogs() (default)
services.AddSingleton<ShellViewModel>();

var provider = services.BuildServiceProvider();
provider.UseAvaloniaViewLocator();                               // Application.DataTemplates
provider.ValidateNavigation(throwOnProblems: Debugger.IsAttached);

desktop.MainWindow = new ShellWindow { DataContext = provider.GetRequiredService<ShellViewModel>() };
await provider.GetRequiredService<INavigationService>().NavigateAsync(Routes.STUDIES);

<Window xmlns:n="https://schemas.outwit.io/navigation">
  <Grid ColumnDefinitions="Auto,*">
    <ItemsControl ItemsSource="{Binding NavigationBar.Items}" />     
    <n:NavigationOutlet Grid.Column="1" Outlet="{Binding Main}" />   
  </Grid>
</Window>

ShellViewModel exposes Main (navigation.Outlet()) and NavigationBar (contributions.Zone(Zones.NAVIGATION_BAR)). No statics, no attached property with a region name, no service lookup from a control.

Views

Explicit registration always wins: nav.AddView<StudyViewModel, StudyView>() or context.Views.Register<StudyViewModel, StudyView>() from a module.

The convention searches the view model's own assembly. Views that live in a different assembly from their view models — a shared view model layer, a per-platform view layer — have to be registered explicitly. That is also the only path that survives trimming.

Dialogs

Both hosts route every UI-initiated close — the window's close button, a click on the overlay backdrop, Escape — through the dialog's CanCloseAsync. Style the generated window with the navigation-dialog class and the overlay with navigation-dialog-overlay. For Material.Avalonia there is a ready adapter: OutWit.Common.MVVM.Navigation.Avalonia.DialogHost, kept in its own package so this one carries no dependency on it. Any other dialog library is an IDialogHost of your own passed to UseDialogHost<T>().

License

Apache-2.0. Part of the OutWit ecosystem.