Toolkit2/Framework/Avalonia/Navigation/NavigationRouteHandler.cs

using Avalonia.Controls.Primitives;
using Avalonia.Interactivity;
using Mediator;

namespace Toolkit.Foundation.Avalonia
{
    public class NavigationRouteHandler : IRequestHandler<NavigationRoute>
    {
        private readonly INavigationRouteDescriptorCollection descriptors;

        public NavigationRouteHandler(INavigationRouteDescriptorCollection descriptors)
        {
            this.descriptors = descriptors;
        }

        public ValueTask<Unit> Handle(NavigationRoute request, CancellationToken cancellationToken)
        {
            if (request.Route is TemplatedControl control)
            {
                void HandleUnloaded(object? sender, RoutedEventArgs args)
                {
                    if (descriptors.FirstOrDefault(x => x.Route == sender) is INavigationRouteDescriptor descriptor)
                    {
                        descriptors.Remove(descriptor);
                    }
                }
                control.Unloaded += HandleUnloaded;
            }

            if (descriptors.FirstOrDefault(x => x.Name == request.Name) is INavigationRouteDescriptor descriptor)
            {
                descriptors.Remove(descriptor);
            }

            descriptors.Add(new NavigationRouteDescriptor(request.Name, request.Route));
            return default;
        }
    }
}