Improve regionadapter

samples/Sample.Avalonia/Regions/ListBoxRegion.cs

@@ -1,11 +1,10 @@
-using AsyncNavigation;
-using AsyncNavigation.Avalonia;
+using AsyncNavigation.Avalonia;
 using Avalonia.Controls;
 using System;
 
 namespace Sample.Avalonia.Regions;
 
-public class ListBoxRegion : ItemsRegion
+public class ListBoxRegion : SelectingItemsRegion
 {
     private readonly ListBox _listBox;
     public ListBoxRegion(string name,
@@ -16,8 +15,4 @@ public ListBoxRegion(string name,
         _listBox = listBox;
         _listBox.AutoScrollToSelectedItem = true;
     }
-    public override void ProcessActivate(NavigationContext navigationContext)
-    {
-        base.ProcessActivate(navigationContext);
-    }
 }

samples/Sample.Avalonia/Views/BView.axaml

@@ -1,22 +1,22 @@
 <UserControl
+    d:DesignHeight="450"
+    d:DesignWidth="800"
+    mc:Ignorable="d"
     x:Class="Sample.Avalonia.Views.BView"
+    x:DataType="vm:BViewModel"
     xmlns="https://github.com/avaloniaui"
-    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
     xmlns:an="https://github.com/NeverMorewd/AsyncNavigation"
     xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
-	xmlns:vm="using:Sample.Common"
-    d:DesignHeight="450"
-    d:DesignWidth="800"
-    mc:Ignorable="d"
-	x:DataType="vm:BViewModel">
+    xmlns:vm="using:Sample.Common"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
     <DockPanel LastChildFill="True">
         <Border
-            HorizontalAlignment="Stretch"
             Background="IndianRed"
             BorderBrush="LemonChiffon"
             BorderThickness="1"
-            DockPanel.Dock="Top">
+            DockPanel.Dock="Top"
+            HorizontalAlignment="Stretch">
             <StackPanel>
                 <TextBlock Text="{Binding Name}" />
                 <TextBlock>
@@ -54,11 +54,11 @@
         </StackPanel>
         <ScrollViewer>
             <ItemsControl an:RegionManager.RegionName="ItemsRegion">
-                <ItemsControl.ItemsPanel>
-                    <ItemsPanelTemplate>
-                        <StackPanel />
-                    </ItemsPanelTemplate>
-                </ItemsControl.ItemsPanel>
+				<ItemsControl.ItemsPanel>
+					<ItemsPanelTemplate>
+						<StackPanel />
+					</ItemsPanelTemplate>
+				</ItemsControl.ItemsPanel>
             </ItemsControl>
         </ScrollViewer>
     </DockPanel>

src/AsyncNavigation.Avalonia/ContentRegion.cs

@@ -12,25 +12,6 @@ public ContentRegion(string name,
         IServiceProvider serviceProvider, 
         bool? useCache) : base(name, contentControl, serviceProvider)
     {
-        ArgumentNullException.ThrowIfNull(contentControl);
-        ArgumentNullException.ThrowIfNull(serviceProvider);
-
-        RegionControlAccessor.ExecuteOn(control =>
-        {
-            control.Tag = this;
-            control.ContentTemplate = new FuncDataTemplate<NavigationContext>((context, np) =>
-            {
-                return context?.IndicatorHost.Value?.Host as Control;
-            });
-
-            control.Bind(
-                ContentControl.ContentProperty,
-                new Binding(nameof(RegionContext.Selected)) { Source = _context, Mode = BindingMode.TwoWay });
-
-        });
-
-
-
         EnableViewCache = useCache ?? true;
         IsSinglePageRegion = true;
     }
@@ -40,6 +21,20 @@ public override NavigationPipelineMode NavigationPipelineMode
         get => NavigationPipelineMode.RenderFirst;
     }
 
+    protected override void InitializeOnRegionCreated(ContentControl control)
+    {
+        base.InitializeOnRegionCreated(control);
+        control.Tag = this;
+        control.ContentTemplate = new FuncDataTemplate<NavigationContext>((context, np) =>
+        {
+            return context?.IndicatorHost.Value?.Host as Control;
+        });
+
+        control.Bind(
+            ContentControl.ContentProperty,
+            new Binding(nameof(RegionContext.Selected)) { Source = _context, Mode = BindingMode.TwoWay });
+    }
+
     public override void Dispose()
     {
         base.Dispose();

src/AsyncNavigation.Avalonia/ItemsRegion.cs

@@ -1,68 +1,17 @@
-using AsyncNavigation.Core;
-using Avalonia.Controls;
-using Avalonia.Controls.Primitives;
-using Avalonia.Controls.Templates;
-using Avalonia.Data;
+using Avalonia.Controls;
 
 namespace AsyncNavigation.Avalonia;
 
-public class ItemsRegion : RegionBase<ItemsRegion, ItemsControl>
+public class ItemsRegion : ItemsRegionBase<ItemsRegion, ItemsControl>
 {
     public ItemsRegion(string name, 
         ItemsControl itemsControl, 
         IServiceProvider serviceProvider, 
-        bool? useCache) : base(name, itemsControl, serviceProvider)
+        bool? useCache) : base(name, itemsControl, serviceProvider, useCache)
     {
-        ArgumentNullException.ThrowIfNull(itemsControl);
-        ArgumentNullException.ThrowIfNull(serviceProvider);
-
-        RegionControlAccessor.ExecuteOn(control =>
-        {
-            // binding the lifetime of region to the control
-            control.Tag = this;
-            control.ItemTemplate = new FuncDataTemplate<NavigationContext>((context, np) =>
-            {
-                return context?.IndicatorHost.Value?.Host as Control;
-            });
-
-            control.Bind(
-               ItemsControl.ItemsSourceProperty,
-               new Binding(nameof(RegionContext.Items)) { Source = _context });
-
-            control.Bind(
-                SelectingItemsControl.SelectedItemProperty,
-                new Binding(nameof(RegionContext.Selected)) { Source = _context, Mode = BindingMode.TwoWay });
-        });
-        EnableViewCache = useCache ?? false;
-        IsSinglePageRegion = false;
-    }
-    public override NavigationPipelineMode NavigationPipelineMode
-    {
-        get => NavigationPipelineMode.RenderFirst;
-    }
-    public override void Dispose()
-    {
-        base.Dispose();
-        _context.Clear();
+
     }
-    public override void ProcessActivate(NavigationContext navigationContext)
-    {
-        if (!_context.Items.Contains(navigationContext))
-            _context.Items.Add(navigationContext);
+}
 
-        _context.Selected = navigationContext;
 
-        RegionControlAccessor.ExecuteOn(control =>
-        {
-            control.ScrollIntoView(navigationContext);
-        });
-    }
 
-    public override void ProcessDeactivate(NavigationContext? navigationContext)
-    {
-        var target = navigationContext ?? _context.Selected;
-        if (target == null)
-            return;
-        _ = _context.Items.Remove(target);
-    }
-}

src/AsyncNavigation.Avalonia/ItemsRegionAdapter.cs

@@ -5,10 +5,6 @@ namespace AsyncNavigation.Avalonia;
 
 public class ItemsRegionAdapter : RegionAdapterBase<ItemsControl>
 {
-    public override bool IsAdapted(ItemsControl control)
-    {
-        return base.IsAdapted(control);
-    }
     public override IRegion CreateRegion(string name, ItemsControl control, IServiceProvider serviceProvider, bool? useCache)
     {
         return new ItemsRegion(name, control, serviceProvider, useCache);

src/AsyncNavigation.Avalonia/ItemsRegionBase.cs

@@ -0,0 +1,72 @@
+using AsyncNavigation.Core;
+using Avalonia.Controls;
+using Avalonia.Controls.Templates;
+using Avalonia.Data;
+using Avalonia.Threading;
+
+namespace AsyncNavigation.Avalonia;
+
+public abstract class ItemsRegionBase<TRegion, TItemsControl>
+    : RegionBase<TRegion, TItemsControl>
+    where TRegion : ItemsRegionBase<TRegion, TItemsControl>
+    where TItemsControl : ItemsControl
+{
+    protected ItemsRegionBase(
+        string name,
+        TItemsControl control,
+        IServiceProvider serviceProvider,
+        bool? useCache)
+        : base(name, control, serviceProvider)
+    {
+        IsSinglePageRegion = false;
+        EnableViewCache = useCache ?? false;
+    }
+
+    public override NavigationPipelineMode NavigationPipelineMode
+        => NavigationPipelineMode.RenderFirst;
+
+    protected override void InitializeOnRegionCreated(TItemsControl control)
+    {
+        base.InitializeOnRegionCreated(control);
+
+        control.Tag = this;
+        control.ItemTemplate = new FuncDataTemplate<NavigationContext>((context, _) =>
+        {
+            return context?.IndicatorHost.Value?.Host as Control;
+        });
+
+        control.Bind(
+            ItemsControl.ItemsSourceProperty,
+            new Binding(nameof(RegionContext.Items)) { Source = _context });
+    }
+
+
+    public override void ProcessActivate(NavigationContext navigationContext)
+    {
+        if (!_context.Items.Contains(navigationContext))
+            _context.Items.Add(navigationContext);
+
+        _context.Selected = navigationContext;
+        // https://github.com/AvaloniaUI/Avalonia/issues/17347
+        Dispatcher.UIThread.RunJobs(DispatcherPriority.Loaded);
+        RegionControlAccessor.ExecuteOn(control =>
+        {
+            control.ScrollIntoView(navigationContext);
+        });
+    }
+
+    public override void ProcessDeactivate(NavigationContext? navigationContext)
+    {
+        var target = navigationContext ?? _context.Selected;
+        if (target == null)
+            return;
+
+        _ = _context.Items.Remove(target);
+    }
+
+    public override void Dispose()
+    {
+        base.Dispose();
+        _context.Clear();
+    }
+}

src/AsyncNavigation.Avalonia/SelectingItemsRegion.cs

@@ -0,0 +1,27 @@
+using AsyncNavigation.Core;
+using Avalonia.Controls.Primitives;
+using Avalonia.Data;
+
+namespace AsyncNavigation.Avalonia;
+
+/// <summary>
+/// Make this class abstract to avoid direct usage.
+/// Because https://github.com/AvaloniaUI/Avalonia/issues/11139
+/// </summary>
+public abstract class SelectingItemsRegion : ItemsRegionBase<SelectingItemsRegion, SelectingItemsControl>
+{
+    protected SelectingItemsRegion(string name, 
+        SelectingItemsControl selectingItemsControl, 
+        IServiceProvider serviceProvider, 
+        bool? useCache) : base(name, selectingItemsControl, serviceProvider, useCache)
+    {
+
+    }
+    protected override void InitializeOnRegionCreated(SelectingItemsControl control)
+    {
+        base.InitializeOnRegionCreated(control);
+        control.Bind(
+            SelectingItemsControl.SelectedItemProperty,
+            new Binding(nameof(RegionContext.Selected)) { Source = _context, Mode = BindingMode.TwoWay });
+    }
+}

src/AsyncNavigation.Avalonia/TabRegion.cs

@@ -12,33 +12,31 @@ public TabRegion(string name,
         TabControl tabControl,
         IServiceProvider serviceProvider,
         bool? useCache) : base(name, tabControl, serviceProvider)
-    {
-        ArgumentNullException.ThrowIfNull(tabControl);
-        ArgumentNullException.ThrowIfNull(serviceProvider);
-
-        RegionControlAccessor.ExecuteOn(control => 
-        {
-            control.Tag = this;
-            control.Bind(ItemsControl.ItemsSourceProperty,
-                new Binding(nameof(RegionContext.Items)) { Source = _context });
-
-            control.Bind(SelectingItemsControl.SelectedItemProperty,
-                new Binding(nameof(RegionContext.Selected)) { Source = _context, Mode = BindingMode.TwoWay });
-
-            control.ContentTemplate = new FuncDataTemplate<NavigationContext>((context, _) =>
-            {
-                return context?.IndicatorHost.Value?.Host as Control;
-            });
-        });
-
-
+    { 
         EnableViewCache = useCache ?? false;
         IsSinglePageRegion = false;
     }
     public override NavigationPipelineMode NavigationPipelineMode
     {
         get => NavigationPipelineMode.ResolveFirst;
     }
+
+    protected override void InitializeOnRegionCreated(TabControl control)
+    {
+        base.InitializeOnRegionCreated(control);
+        control.Tag = this;
+        control.Bind(ItemsControl.ItemsSourceProperty,
+            new Binding(nameof(RegionContext.Items)) { Source = _context });
+
+        control.Bind(SelectingItemsControl.SelectedItemProperty,
+            new Binding(nameof(RegionContext.Selected)) { Source = _context, Mode = BindingMode.TwoWay });
+
+        control.ContentTemplate = new FuncDataTemplate<NavigationContext>((context, _) =>
+        {
+            return context?.IndicatorHost.Value?.Host as Control;
+        });
+    }
+
     public override void Dispose()
     {
         base.Dispose();