introduce a TransientNavigationStore to share objects from one state to the next state

Toolkit.Avalonia/FrameHandler.cs

@@ -7,7 +7,7 @@ using Toolkit.UI.Controls.Avalonia;
 
 namespace Toolkit.Avalonia;
 
-public class FrameHandler :
+public class FrameHandler(ITransientNavigationStore<Frame> navigationStore) :
     INotificationHandler<NavigateEventArgs<Frame>>,
     INotificationHandler<NavigateBackEventArgs<Frame>>
 {
@@ -18,19 +18,16 @@ public class FrameHandler :
             frame.NavigationPageFactory ??= new NavigationPageFactory();
             if (args.Template is Control control)
             {
-                void NavigatedTo(Control sender)
+                void Navigated(Control sender)
                 {
-                    async void HandleNavigatedTo(object? _,
+                    async void HandleNavigatedTo(object? _, NavigationEventArgs __)
-                        NavigationEventArgs __)
                     {
-                        async void HandleNavigatingFrom(object? _,
+                        async void HandleNavigatingFrom(object? _, NavigatingCancelEventArgs args)
-                            NavigatingCancelEventArgs args)
                         {
                             sender.RemoveHandler(Frame.NavigatingFromEvent, HandleNavigatingFrom);
                             control.Unloaded -= HandleUnloaded;
 
-                            async void HandleNavigatedFrom(object? _,
+                            async void HandleNavigatedFrom(object? _, NavigationEventArgs args)
-                                NavigationEventArgs args)
                             {
                                 sender.RemoveHandler(Frame.NavigatedFromEvent, HandleNavigatedFrom);
                                 if (sender.DataContext is object content)
@@ -40,9 +37,11 @@ public class FrameHandler :
                                         await deactivated.OnDeactivated();
                                     }
 
-                                    if (content is not IKeepAlive)
-                                    {
                                     if (content is IDisposable disposable)
+                                    {
+                                        FrameNavigationOptions? options = navigationStore.Get<FrameNavigationOptions>(frame);
+                                        if (options is not FrameNavigationOptions frameOptions ||
+                                            !frameOptions.IsNavigationStackEnabled)
                                         {
                                             disposable.Dispose();
                                         }
@@ -51,6 +50,7 @@ public class FrameHandler :
                             }
 
                             sender.AddHandler(Frame.NavigatedFromEvent, HandleNavigatedFrom);
+
                             if (sender.DataContext is object content)
                             {
                                 if (content is IConfirmation confirmation && 
@@ -106,7 +106,6 @@ public class FrameHandler :
                 }
 
                 control.DataContext = args.Content;
-                NavigatedTo(control);
 
                 FrameNavigationOptions navigationOptions = new();
                 List<Action> postNavigateActions = [];
@@ -133,22 +132,19 @@ public class FrameHandler :
 
                 if (args.Parameters is not null)
                 {
-                    if (args.Parameters.TryGetValue("Transition",
+                    if (args.Parameters.TryGetValue("Transition", out object? transition))
-                        out object? transition))
                     {
                         switch ($"{transition}")
                         {
                             case "Suppress":
-                                navigationOptions.TransitionInfoOverride =
+                                navigationOptions.TransitionInfoOverride = new SuppressNavigationTransitionInfo();
-                                    new SuppressNavigationTransitionInfo();
                                 break;
 
                             case "FromLeft":
                             case "FromRight":
                             case "FromTop":
                             case "FromBottom":
-                                navigationOptions.TransitionInfoOverride =
+                                navigationOptions.TransitionInfoOverride = new SlideNavigationTransitionInfo
-                                    new SlideNavigationTransitionInfo
                                 {
                                     Effect = Enum.Parse<SlideNavigationTransitionEffect>($"{transition}")
                                 };
@@ -156,8 +152,7 @@ public class FrameHandler :
                         }
                     }
 
-                    if (args.Parameters.TryGetValue("IsBackStackEnabled",
+                    if (args.Parameters.TryGetValue("IsBackStackEnabled", out object? isBackStackEnabled))
-                        out object? isBackStackEnabled))
                     {
                         if (isBackStackEnabled is bool value)
                         {
@@ -165,8 +160,7 @@ public class FrameHandler :
                         }
                     }
 
-                    if (args.Parameters.TryGetValue("ClearBackStack",
+                    if (args.Parameters.TryGetValue("ClearBackStack", out object? clearBackStack))
-                        out object? clearBackStack))
                     {
                         if (clearBackStack is bool clearBool)
                         {
@@ -178,8 +172,7 @@ public class FrameHandler :
 
                         if (clearBackStack is string clearString)
                         {
-                            if (clearString.StartsWith('[') && clearString.EndsWith(']') &&
+                            if (clearString.StartsWith('[') && clearString.EndsWith(']') && clearString.Contains('-'))
-                                clearString.Contains('-'))
                             {
                                 string range = clearString.Trim('[', ']');
                                 string[] parts = range.Split('-');
@@ -202,6 +195,9 @@ public class FrameHandler :
                     }
                 }
 
+                Navigated(control);
+
+                navigationStore.Set(frame, navigationOptions);
                 frame.NavigateFromObject(control, navigationOptions);
 
                 foreach (Action postAction in postNavigateActions)

Toolkit.Avalonia/IServiceCollectionExtensions.cs

@@ -33,7 +33,10 @@ public static class IServiceCollectionExtensions
         services.AddHandler<ClassicDesktopStyleApplicationHandler>(nameof(IClassicDesktopStyleApplicationLifetime));
         services.AddHandler<SingleViewApplicationHandler>(nameof(ISingleViewApplicationLifetime));
         services.AddHandler<ContentControlHandler>(nameof(ContentControl));
+
         services.AddHandler<FrameHandler>(nameof(Frame));
+        services.TryAddSingleton<ITransientNavigationStore<Frame>, TransientNavigationStore<Frame>>();
+
         services.AddHandler<ContentDialogHandler>(nameof(ContentDialog));
         services.AddHandler<TaskDialogHandler>(nameof(TaskDialog));
 
@@ -66,7 +69,11 @@ public static class IServiceCollectionExtensions
                 services.AddHandler<SelectFilesHandler>();
 
                 services.AddHandler<ContentControlHandler>(nameof(ContentControl));
+
                 services.AddHandler<FrameHandler>(nameof(Frame));
+
+                services.TryAddSingleton(provider.GetRequiredService<ITransientNavigationStore<Frame>>());
+
                 services.AddHandler<ContentDialogHandler>(nameof(ContentDialog));
                 services.AddHandler<TaskDialogHandler>(nameof(TaskDialog));
             })));

Toolkit.Avalonia/ITransientNavigationStore.cs

@@ -0,0 +1,15 @@
+namespace Toolkit.Avalonia;
+
+public interface ITransientNavigationStore<TControl> 
+    where TControl : class
+{
+    void Clear();
+
+    T? Get<T>(TControl control)
+           where T : class;
+  
+    void Remove(TControl control);
+
+    void Set(TControl control,
+        object parameters);
+}

Toolkit.Avalonia/TransientNavigationStore.cs

@@ -0,0 +1,36 @@
+namespace Toolkit.Avalonia;
+
+public class TransientNavigationStore<TControl> : ITransientNavigationStore<TControl>
+    where TControl : class
+{
+    private readonly Dictionary<TControl, Dictionary<Type, object>> controlDataMap = [];
+
+    public void Set(TControl control, 
+        object parameters)
+    {
+        if (!controlDataMap.TryGetValue(control, out var typeMap))
+        {
+            typeMap = new Dictionary<Type, object>();
+            controlDataMap[control] = typeMap;
+        }
+
+        typeMap[parameters.GetType()] = parameters;
+    }
+
+    public T? Get<T>(TControl control)
+        where T : class
+    {
+        if (controlDataMap.TryGetValue(control, out var typeMap) &&
+            typeMap.TryGetValue(typeof(T), out var parameters))
+        {
+            typeMap.Remove(typeof(T));
+            return parameters as T;
+        }
+
+        return default;
+    }
+
+    public void Remove(TControl control) => controlDataMap.Remove(control);
+
+    public void Clear() => controlDataMap.Clear();
+}

Toolkit.Foundation/ContentFactory.cs

@@ -1,9 +1,10 @@
 namespace Toolkit.Foundation;
 
 public class ContentFactory(IServiceProvider provider,
-    IServiceFactory factory) : IContentFactory
+    IServiceFactory factory) : 
+    IContentFactory
 {
-    public Task<object?> CreateAsync(IContentTemplateDescriptor descriptor,
+    public object? Create(IContentTemplateDescriptor descriptor,
         object[] parameters)
     {
         object? content = parameters is { Length: > 0 }
@@ -22,6 +23,6 @@ public class ContentFactory(IServiceProvider provider,
                     }
                 }, descriptor.Key);
 
-        return Task.FromResult<object?>(content);
+        return content;
     }
 }

Toolkit.Foundation/IContentFactory.cs

@@ -2,7 +2,7 @@
 {
     public interface IContentFactory
     {
-        Task<object?> CreateAsync(IContentTemplateDescriptor descriptor,
+        object? Create(IContentTemplateDescriptor descriptor,
-            object[] resolvedArguments);
+            object[] parameters);
     }
 }

Toolkit.Foundation/IKeepAlive.cs

@@ -1,3 +0,0 @@
-namespace Toolkit.Foundation;
-
-public interface IKeepAlive;

Toolkit.Foundation/Navigation.cs

@@ -62,7 +62,7 @@ public class Navigation(IServiceProvider provider,
 
                     if (region is not null)
                     {
-                        object? content = await contentFactory.CreateAsync(descriptor, resolvedArguments);
+                        object? content = contentFactory.Create(descriptor, resolvedArguments);
                         if (content is not null)
                         {
                             Type navigationType = region is Type type ? type : region.GetType();

Toolkit.Foundation/ObservableCollection.cs

@@ -46,6 +46,8 @@ public partial class ObservableCollection<TViewModel> :
     [ObservableProperty]
     private int count;
 
+    private Func<TViewModel>? defaultSelectionFactory;
+
     [ObservableProperty]
     private bool isActivated;
 
@@ -145,86 +147,27 @@ public partial class ObservableCollection<TViewModel> :
         }
     }
 
-    private Func<TViewModel>? defaultSelectionFactory;
+    public void Activate(Func<ActivationBuilder> activateDelegate,
-
+        bool reset = false)
-    public void SetSource(IList<TViewModel> source,
-        Func<TViewModel>? defaultSelectionFactory)
     {
-        foreach (TViewModel item in source)
+        if (reset)
         {
-            Add(item);
-        }
-
-        if (defaultSelectionFactory is not null)
-        {
-            this.defaultSelectionFactory = defaultSelectionFactory;
-            SelectedItem = defaultSelectionFactory.Invoke();
-        }
-
-        if (source is INotifyCollectionChanged observableSource)
-        {
-            observableSource.CollectionChanged -= SourceCollectionChanged;
-            observableSource.CollectionChanged += SourceCollectionChanged;
-        }
-    }
-
-    private void SourceCollectionChanged(object? sender,
-        NotifyCollectionChangedEventArgs args)
-    {
-        switch (args.Action)
-        {
-            case NotifyCollectionChangedAction.Add:
-                if (args.NewItems is not null)
-                {
-                    foreach (TViewModel newItem in args.NewItems)
-                    {
-                        Add(newItem);
-                    }
-                }
-                break;
-
-            case NotifyCollectionChangedAction.Remove:
-                if (args.OldItems is not null)
-                {
-                    foreach (TViewModel oldItem in args.OldItems)
-                    {
-                        if (this.FirstOrDefault(x => x.Equals(oldItem)) is TViewModel removedItem)
-                        {
-                            Remove(removedItem);
-                        }
-                    }
-                }
-                break;
-
-            case NotifyCollectionChangedAction.Reset:
-
             Clear();
-                if (sender is IEnumerable<TViewModel> collection)
-                {
-                    foreach (TViewModel item in collection)
-                    {
-                        Add(item);
         }
 
-                    if (defaultSelectionFactory is not null)
+        ActivationBuilder builder = activateDelegate.Invoke();
-                    {
+        Publisher.Publish(builder.Value, builder.Key);
-                        SelectedItem = defaultSelectionFactory.Invoke();
-                    }
-                }
-                break;
-        }
     }
 
-    public virtual Task OnActivated()
+    public void Activate(bool reset = false)
     {
-        IsActivated = true;
+        if (reset)
-        while (pendingEvents.Count > 0)
         {
-            object current = pendingEvents.Dequeue();
+            Clear();
-            Handle((dynamic)current);
         }
 
-        return Task.CompletedTask;
+        ActivationBuilder builder = ActivationBuilder();
+        Publisher.PublishUI(builder.Value, builder.Key);
     }
 
     public TViewModel Add<T>(params object?[] parameters)
@@ -285,14 +228,6 @@ public partial class ObservableCollection<TViewModel> :
         }
     }
 
-    public void Reset(Action<ObservableCollection<TViewModel>> factory, bool disposeItems = true)
-    {
-        SelectedItem = default;
-
-        Clear(disposeItems);
-        factory.Invoke(this);
-    }
-
     public void Clear(bool disposeItems = false)
     {
         isClearing = true;
@@ -342,33 +277,12 @@ public partial class ObservableCollection<TViewModel> :
     void ICollection.CopyTo(Array array, int index) =>
         collection.CopyTo((TViewModel[])array, index);
 
-    public virtual Task OnDeactivated()
-    {
-        IsActivated = false;
-        return Task.CompletedTask;
-    }
-
-    public virtual Task OnDeactivating() =>
-        Task.CompletedTask;
-
     public virtual void Dispose()
     {
         GC.SuppressFinalize(this);
         Disposer.Dispose(this);
     }
 
-    public void Activate(Func<ActivationBuilder> activateDelegate,
-        bool reset = false)
-    {
-        if (reset)
-        {
-            Clear();
-        }
-
-        ActivationBuilder builder = activateDelegate.Invoke();
-        Publisher.Publish(builder.Value, builder.Key);
-    }
-
     public IEnumerator<TViewModel> GetEnumerator() =>
         collection.GetEnumerator();
 
@@ -505,10 +419,6 @@ public partial class ObservableCollection<TViewModel> :
         IsCompatibleObject(value) ?
         IndexOf((TViewModel)value!) : -1;
 
-    public virtual void OnInitialize()
-    {
-    }
-
     [RelayCommand]
     public virtual void Initialize()
     {
@@ -519,37 +429,12 @@ public partial class ObservableCollection<TViewModel> :
 
         IsInitialized = true;
         Subscriber.Subscribe(this);
+
         OnInitialize();
 
         Activate();
     }
 
-    public bool Replace<T>(int index, 
-        params object?[] parameters)
-        where T :
-        TViewModel
-    {
-        if (index <= Count - 1)
-        {
-            RemoveItem(index);
-        }
-        else
-        {
-            index = Count;
-        }
-
-        T? item = Factory.Create<T>(args =>
-        {
-            if (args is IInitialization initialization)
-            {
-                initialization.Initialize();
-            }
-        }, parameters);
-
-        Insert(index, item);
-        return true;
-    }
-
     public TViewModel Insert<T>(int index = 0,
         params object?[] parameters)
         where T :
@@ -634,6 +519,31 @@ public partial class ObservableCollection<TViewModel> :
         return true;
     }
 
+    public virtual Task OnActivated()
+    {
+        IsActivated = true;
+        while (pendingEvents.Count > 0)
+        {
+            object current = pendingEvents.Dequeue();
+            Handle((dynamic)current);
+        }
+
+        return Task.CompletedTask;
+    }
+
+    public virtual Task OnDeactivated()
+    {
+        IsActivated = false;
+        return Task.CompletedTask;
+    }
+
+    public virtual Task OnDeactivating() =>
+        Task.CompletedTask;
+
+    public virtual void OnInitialize()
+    {
+    }
+
     public bool Remove(TViewModel item)
     {
         int index = collection.IndexOf(item);
@@ -669,6 +579,32 @@ public partial class ObservableCollection<TViewModel> :
     public void RemoveAt(int index) =>
         RemoveItem(index);
 
+    public bool Replace<T>(int index,
+        params object?[] parameters)
+        where T :
+        TViewModel
+    {
+        if (index <= Count - 1)
+        {
+            RemoveItem(index);
+        }
+        else
+        {
+            index = Count;
+        }
+
+        T? item = Factory.Create<T>(args =>
+        {
+            if (args is IInitialization initialization)
+            {
+                initialization.Initialize();
+            }
+        }, parameters);
+
+        Insert(index, item);
+        return true;
+    }
+
     public bool Replace(int index,
         TViewModel item)
     {
@@ -685,6 +621,14 @@ public partial class ObservableCollection<TViewModel> :
         return true;
     }
 
+    public void Reset(Action<ObservableCollection<TViewModel>> factory, bool disposeItems = true)
+    {
+        SelectedItem = default;
+
+        Clear(disposeItems);
+        factory.Invoke(this);
+    }
+
     public void Revert()
     {
         foreach (object trackedProperty in trackedProperties.Values)
@@ -693,15 +637,24 @@ public partial class ObservableCollection<TViewModel> :
         }
     }
 
-    public void Activate(bool reset = false)
+    public void SetSource(IList<TViewModel> source,                                                                                                                                                                                       Func<TViewModel>? defaultSelectionFactory)
     {
-        if (reset)
+        foreach (TViewModel item in source)
         {
-            Clear();
+            Add(item);
         }
 
-        ActivationBuilder builder = ActivationBuilder();
+        if (defaultSelectionFactory is not null)
-        Publisher.PublishUI(builder.Value, builder.Key);
+        {
+            this.defaultSelectionFactory = defaultSelectionFactory;
+            SelectedItem = defaultSelectionFactory.Invoke();
+        }
+
+        if (source is INotifyCollectionChanged observableSource)
+        {
+            observableSource.CollectionChanged -= SourceCollectionChanged;
+            observableSource.CollectionChanged += SourceCollectionChanged;
+        }
     }
 
     public void Track<T>(string propertyName, Func<T> getter, Action<T> setter)
@@ -725,7 +678,7 @@ public partial class ObservableCollection<TViewModel> :
         Disposer.Add(this, item);
         Disposer.Add(item, Disposable.Create(() =>
         {
-            if (item is IRemovable && !isClearing)
+            if (item is IDisposable && !isClearing)
             {
                 if (item is IList collection)
                 {
@@ -739,6 +692,10 @@ public partial class ObservableCollection<TViewModel> :
         collection.Insert(index > Count ? Count : index, item);
     }
 
+    protected virtual void OnSelectedItemChanged()
+    {
+    }
+
     protected virtual void RemoveItem(int index) =>
         collection.RemoveAt(index);
 
@@ -782,10 +739,52 @@ public partial class ObservableCollection<TViewModel> :
         OnSelectedItemChanged();
     }
 
-    protected virtual void OnSelectedItemChanged()
+    private void SourceCollectionChanged(object? sender,
+        NotifyCollectionChangedEventArgs args)
     {
+        switch (args.Action)
+        {
+            case NotifyCollectionChangedAction.Add:
+                if (args.NewItems is not null)
+                {
+                    foreach (TViewModel newItem in args.NewItems)
+                    {
+                        Add(newItem);
+                    }
+                }
+                break;
+
+            case NotifyCollectionChangedAction.Remove:
+                if (args.OldItems is not null)
+                {
+                    foreach (TViewModel oldItem in args.OldItems)
+                    {
+                        if (this.FirstOrDefault(x => x.Equals(oldItem)) is TViewModel removedItem)
+                        {
+                            Remove(removedItem);
+                        }
+                    }
+                }
+                break;
+
+            case NotifyCollectionChangedAction.Reset:
+
+                Clear();
+                if (sender is IEnumerable<TViewModel> collection)
+                {
+                    foreach (TViewModel item in collection)
+                    {
+                        Add(item);
                     }
 
+                    if (defaultSelectionFactory is not null)
+                    {
+                        SelectedItem = defaultSelectionFactory.Invoke();
+                    }
+                }
+                break;
+        }
+    }
     private void UpdateSelection(TViewModel item)
     {
         if (item is ISelectable newSelection)