Navigation in Avalonia

2022-12-05 19:39:13 +00:00
parent 855a4b98d2
commit 358926a5d4
17 changed files with 1660 additions and 59 deletions
@@ -0,0 +1,89 @@
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Controls.Primitives;
+using Avalonia.Data;
+using Avalonia.Interactivity;
+using Avalonia.Markup.Xaml;
+
+namespace Toolkit.Foundation.Avalonia
+{
+    public class NavigationRouteExtension : MarkupExtension
+    {
+        private static readonly AttachedProperty<object> RouteProperty =
+            AvaloniaProperty.RegisterAttached<NavigationRouteExtension, Control, object>("Route");
+
+        private readonly string name;
+        private readonly Binding? routeBinding;
+
+        public NavigationRouteExtension(object route, string name)
+        {
+            routeBinding = route is Binding toBinding ? toBinding : route.ToBinding();
+            this.name = name;
+        }
+
+        private bool TryGetBinding(AvaloniaObject sender, out object? binding)
+        {
+            binding = sender.GetValue(StyledElement.DataContextProperty);
+            return binding is not null;
+        }
+
+        public override object? ProvideValue(IServiceProvider serviceProvider)
+        {
+            if (serviceProvider.GetService(typeof(IProvideValueTarget)) is IProvideValueTarget target)
+            {
+                if (target.TargetObject is TemplatedControl control)
+                {
+                    if (routeBinding is not null)
+                    {
+                        if (!TryGetBinding(control, out object? binding))
+                        {
+                            void HandleDataContextChanged(object? sender, EventArgs args)
+                            {
+                                if (TryGetBinding(control, out binding))
+                                {
+                                    control.Loaded -= HandleLoaded;
+                                    control.Bind(RouteProperty, routeBinding);
+
+                                    if (control?.GetValue(RouteProperty) is INavigationRouter router)
+                                    {
+                                        router.Register(name, control);
+                                        control.ClearValue(RouteProperty);
+                                    }
+                                }
+                            }
+
+                            control.DataContextChanged += HandleDataContextChanged;
+
+                            void HandleLoaded(object? sender, RoutedEventArgs args)
+                            {
+                                control.Loaded -= HandleLoaded;
+                                if (TryGetBinding(control, out binding))
+                                {
+                                    control.Bind(RouteProperty, routeBinding);
+                                    if (control?.GetValue(RouteProperty) is INavigationRouter router)
+                                    {
+                                        router.Register(name, control);
+                                        control.ClearValue(RouteProperty);
+                                    }
+                                }
+                            }
+
+                            control.Loaded += HandleLoaded;
+                        }
+                        else
+                        {
+                            control.Bind(RouteProperty, routeBinding);
+                            if (control?.GetValue(RouteProperty) is INavigationRouter router)
+                            {
+                                router.Register(name, control);
+                                control.ClearValue(RouteProperty);
+                            }
+                        }
+                    }
+                }
+            }
+
+            return null;
+        }
+    }
+}