Toolkit2/Framework/Avalonia/Navigation/NavigateBackHandler.cs

using Avalonia.Controls;
using Avalonia.Controls.Primitives;
using FluentAvalonia.UI.Controls;
using Mediator;

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

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

        public ValueTask<Unit> Handle(NavigateBack request, CancellationToken cancellationToken)
        {
            if (descriptors.FirstOrDefault(x => request.Route is string { } name && name == x.Name) is NavigationRouteDescriptor descriptor)
            {
                if (descriptor.Route is ContentControl { Content: TemplatedControl content })
                {
                    if (content.DataContext is IDisposable disposable)
                    {
                        disposable.Dispose();
                    }
                }

                if (descriptor.Route is Frame frame)
                {
                    frame.GoBack();
                }
            }

            return default;
        }
    }
}