Merge branch 'fixes/clearTypeRendering' of https://github.com/Gillibald/Avalonia into fixes/clearTypeRendering

samples/ControlCatalog/Pages/ListBoxPage.xaml

@@ -32,6 +32,7 @@
     </StackPanel>
     <ListBox Items="{Binding Items}"
              Selection="{Binding Selection}"
+             DisplayMemberBinding="{Binding (viewModels:ItemModel).ID, StringFormat='{}Item {0:N0}'}"
              AutoScrollToSelectedItem="{Binding AutoScrollToSelectedItem}"
              SelectionMode="{Binding SelectionMode^}"
              WrapSelection="{Binding WrapSelection}"/>

samples/ControlCatalog/Pages/TabControlPage.xaml

@@ -53,14 +53,8 @@
                 <TabControl
                     Items="{Binding Tabs}"
                     Margin="0 16"
+                    HeaderDisplayMemberBinding="{Binding Header, x:DataType=viewModels:TabControlPageViewModelItem}"
                     TabStripPlacement="{Binding TabPlacement}">
-                    <TabControl.ItemTemplate>
-                        <DataTemplate x:DataType="viewModels:TabControlPageViewModelItem">
-                            <TextBlock
-                                Text="{Binding Header}">
-                            </TextBlock>
-                        </DataTemplate>
-                    </TabControl.ItemTemplate>
                     <TabControl.ContentTemplate>
                         <DataTemplate x:DataType="viewModels:TabControlPageViewModelItem">
                             <StackPanel Orientation="Vertical" Spacing="8">

samples/ControlCatalog/ViewModels/ListBoxPageViewModel.cs

@@ -4,6 +4,7 @@ using System.Linq;
 using System.Reactive;
 using Avalonia.Controls;
 using Avalonia.Controls.Selection;
+using ControlCatalog.Pages;
 using MiniMvvm;
 
 namespace ControlCatalog.ViewModels
@@ -20,9 +21,9 @@ namespace ControlCatalog.ViewModels
 
         public ListBoxPageViewModel()
         {
-            Items = new ObservableCollection<string>(Enumerable.Range(1, 10000).Select(i => GenerateItem()));
+            Items = new ObservableCollection<ItemModel>(Enumerable.Range(1, 10000).Select(i => GenerateItem()));
             
-            Selection = new SelectionModel<string>();
+            Selection = new SelectionModel<ItemModel>();
             Selection.Select(1);
 
             _selectionMode = this.WhenAnyValue(
@@ -58,8 +59,8 @@ namespace ControlCatalog.ViewModels
             });
         }
 
-        public ObservableCollection<string> Items { get; }
+        public ObservableCollection<ItemModel> Items { get; }
-        public SelectionModel<string> Selection { get; }
+        public SelectionModel<ItemModel> Selection { get; }
         public IObservable<SelectionMode> SelectionMode => _selectionMode;
 
         public bool Multiple
@@ -96,6 +97,31 @@ namespace ControlCatalog.ViewModels
         public MiniCommand RemoveItemCommand { get; }
         public MiniCommand SelectRandomItemCommand { get; }
 
-        private string GenerateItem() => $"Item {_counter++.ToString()}";
+        private ItemModel GenerateItem() => new ItemModel(_counter ++);  
+    }
+
+    /// <summary>
+    /// An Item model for the <see cref="ListBoxPage"/>
+    /// </summary>
+    public class ItemModel
+    {
+        /// <summary>
+        /// Creates a new ItemModel with the given ID
+        /// </summary>
+        /// <param name="id">The ID to display</param>
+        public ItemModel(int id)
+        {
+            ID = id;
+        }
+
+        /// <summary>
+        /// The ID of this Item
+        /// </summary>
+        public int ID { get; }
+
+        public override string ToString()
+        {
+            return $"Item {ID}";
+        }
     }
 }

src/Avalonia.Base/Rendering/Composition/Animations/KeyFrameAnimationInstance.cs

@@ -128,8 +128,11 @@ namespace Avalonia.Rendering.Composition.Animations
 
                     left = kf;
                     right = _keyFrames[c + 1];
-                    break;
                 }
+                else if (c == 0)
+                    return ExpressionVariant.Create(GetKeyFrame(ref ctx, kf));
+                else
+                    break;
             }
 
             var keyProgress = Math.Max(0, Math.Min(1, (iterationProgress - left.Key) / (right.Key - left.Key)));

src/Avalonia.Base/Rendering/Composition/CompositingRenderer.cs

@@ -146,8 +146,18 @@ public class CompositingRenderer : IRendererWithCompositor
                 return result == 0 ? lhs.index.CompareTo(rhs.index) : result;
             });
         }
-
+        
-        if (compositionChildren.Count == visualChildren.Count)
+        var childVisual = v.ChildCompositionVisual;
+        
+        // Check if the current visual somehow got migrated to another compositor
+        if (childVisual != null && childVisual.Compositor != v.CompositionVisual.Compositor)
+            childVisual = null;
+        
+        var expectedCount = visualChildren.Count;
+        if (childVisual != null)
+            expectedCount++;
+        
+        if (compositionChildren.Count == expectedCount)
         {
             bool mismatch = false;
             if (sortedChildren != null)
@@ -167,6 +177,9 @@ public class CompositingRenderer : IRendererWithCompositor
                         break;
                     }
 
+            if (childVisual != null &&
+                !ReferenceEquals(compositionChildren[compositionChildren.Count - 1], childVisual))
+                mismatch = true;
 
             if (!mismatch)
             {
@@ -193,6 +206,9 @@ public class CompositingRenderer : IRendererWithCompositor
                 if (compositionChild != null)
                     compositionChildren.Add(compositionChild);
             }
+
+        if (childVisual != null)
+            compositionChildren.Add(childVisual);
     }
 
     private void UpdateCore()

src/Avalonia.Base/Rendering/Composition/Compositor.Factories.cs

@@ -29,4 +29,7 @@ public partial class Compositor
     public ImplicitAnimationCollection CreateImplicitAnimationCollection() => new ImplicitAnimationCollection(this);
 
     public CompositionAnimationGroup CreateAnimationGroup() => new CompositionAnimationGroup(this);
+
+    public CompositionSolidColorVisual CreateSolidColorVisual() =>
+        new(this, new ServerCompositionSolidColorVisual(Server));
 }

src/Avalonia.Base/Rendering/Composition/ElementCompositionPreview.cs

@@ -1,5 +1,8 @@
 // Special license applies <see href="https://raw.githubusercontent.com/AvaloniaUI/Avalonia/master/src/Avalonia.Base/Rendering/Composition/License.md">License.md</see>
 
+using System;
+using Avalonia.VisualTree;
+
 namespace Avalonia.Rendering.Composition;
 
 /// <summary>
@@ -13,4 +16,22 @@ public static class ElementComposition
     /// <param name="visual"></param>
     /// <returns></returns>
     public static CompositionVisual? GetElementVisual(Visual visual) => visual.CompositionVisual;
+
+    /// <summary>
+    /// Sets a custom <see cref="CompositionVisual"/> as the last child of the element’s visual tree.
+    /// </summary>
+    public static void SetElementChildVisual(Visual visual, CompositionVisual? compositionVisual)
+    {
+        if (compositionVisual != null && visual.CompositionVisual != null &&
+            compositionVisual.Compositor != visual.CompositionVisual.Compositor)
+            throw new InvalidOperationException("Composition visuals belong to different compositor instances");
+        
+        visual.ChildCompositionVisual = compositionVisual;
+        visual.GetVisualRoot()?.Renderer.RecalculateChildren(visual);
+    }
+
+    /// <summary>
+    /// Retrieves a <see cref="CompositionVisual"/> object previously set by a call to <see cref="SetElementChildVisual" />.
+    /// </summary>
+    public static CompositionVisual? GetElementChildVisual(Visual visual) => visual.ChildCompositionVisual;
 }

src/Avalonia.Base/Rendering/Composition/Server/ServerCompositionSolidColorVisual.cs

@@ -0,0 +1,11 @@
+using Avalonia.Media.Immutable;
+
+namespace Avalonia.Rendering.Composition.Server;
+
+internal partial class ServerCompositionSolidColorVisual
+{
+    protected override void RenderCore(CompositorDrawingContextProxy canvas, Rect currentTransformedClip)
+    {
+        canvas.DrawRectangle(new ImmutableSolidColorBrush(Color), null, new Rect(0, 0, Size.X, Size.Y));
+    }
+}

src/Avalonia.Base/Rendering/Composition/Server/ServerCompositionVisual.cs

@@ -48,7 +48,7 @@ namespace Avalonia.Rendering.Composition.Server
             if (Opacity != 1)
                 canvas.PushOpacity(Opacity);
             var boundsRect = new Rect(new Size(Size.X, Size.Y));
-            if(ClipToBounds)
+            if (ClipToBounds && !HandlesClipToBounds)
                 canvas.PushClip(Root!.SnapToDevicePixels(boundsRect));
             if (Clip != null) 
                 canvas.PushGeometryClip(Clip);
@@ -65,11 +65,13 @@ namespace Avalonia.Rendering.Composition.Server
                 canvas.PopOpacityMask();
             if (Clip != null)
                 canvas.PopGeometryClip();
-            if (ClipToBounds)
+            if (ClipToBounds && !HandlesClipToBounds)
                 canvas.PopClip();
             if(Opacity != 1)
                 canvas.PopOpacity();
         }
+
+        protected virtual bool HandlesClipToBounds => false;
         
         private ReadbackData _readback0, _readback1, _readback2;
 

src/Avalonia.Base/Threading/DispatcherPriority.cs

@@ -45,32 +45,37 @@ namespace Avalonia.Threading
         /// <summary>
         /// The job will be processed after other non-idle operations have completed.
         /// </summary>
-        public static readonly DispatcherPriority Background = new(1);
+        public static readonly DispatcherPriority Background = new(MinValue + 1);
 
         /// <summary>
         /// The job will be processed with the same priority as input.
         /// </summary>
-        public static readonly DispatcherPriority Input = new(2);
+        public static readonly DispatcherPriority Input = new(Background + 1);
 
         /// <summary>
         /// The job will be processed after layout and render but before input.
         /// </summary>
-        public static readonly DispatcherPriority Loaded = new(3);
+        public static readonly DispatcherPriority Loaded = new(Input + 1);
-        
+
         /// <summary>
         /// The job will be processed with the same priority as render.
         /// </summary>
-        public static readonly DispatcherPriority Render = new(5);
+        public static readonly DispatcherPriority Render = new(Loaded + 1);
-        
+
         /// <summary>
         /// The job will be processed with the same priority as composition updates.
         /// </summary>
-        public static readonly DispatcherPriority Composition = new(6);
+        public static readonly DispatcherPriority Composition = new(Render + 1);
-        
+
         /// <summary>
-        /// The job will be processed with the same priority as render.
+        /// The job will be processed with before composition updates.
+        /// </summary>
+        public static readonly DispatcherPriority PreComposition = new(Composition + 1);
+
+        /// <summary>
+        /// The job will be processed with the same priority as layout.
         /// </summary>
-        public static readonly DispatcherPriority Layout = new(7);
+        public static readonly DispatcherPriority Layout = new(PreComposition + 1);
 
         /// <summary>
         /// The job will be processed with the same priority as data binding.
@@ -80,7 +85,7 @@ namespace Avalonia.Threading
         /// <summary>
         /// The job will be processed before other asynchronous operations.
         /// </summary>
-        public static readonly DispatcherPriority Send = new(8);
+        public static readonly DispatcherPriority Send = new(Layout + 1);
 
         /// <summary>
         /// Maximum possible priority
@@ -123,4 +128,4 @@ namespace Avalonia.Threading
         /// <inheritdoc />
         public int CompareTo(DispatcherPriority other) => Value.CompareTo(other.Value);
     }
-}
+}

src/Avalonia.Base/Visual.cs

@@ -292,6 +292,7 @@ namespace Avalonia
         protected IRenderRoot? VisualRoot => _visualRoot ?? (this as IRenderRoot);
 
         internal CompositionDrawListVisual? CompositionVisual { get; private set; }
+        internal CompositionVisual? ChildCompositionVisual { get; set; }
         
         public bool HasNonUniformZIndexChildren { get; private set; }
 
@@ -452,12 +453,15 @@ namespace Avalonia
             }
         }
 
+        private protected virtual CompositionDrawListVisual CreateCompositionVisual(Compositor compositor)
+            => new CompositionDrawListVisual(compositor,
+                new ServerCompositionDrawListVisual(compositor.Server, this), this);
+        
         internal CompositionVisual AttachToCompositor(Compositor compositor)
         {
             if (CompositionVisual == null || CompositionVisual.Compositor != compositor)
             {
-                CompositionVisual = new CompositionDrawListVisual(compositor,
+                CompositionVisual = CreateCompositionVisual(compositor);
-                    new ServerCompositionDrawListVisual(compositor.Server, this), this);
             }
 
             return CompositionVisual;

src/Avalonia.Base/composition-schema.xml

@@ -27,6 +27,9 @@
         <Property Name="OpacityMaskBrush" Type="Avalonia.Media.IBrush?" Internal="true" />
     </Object>
     <Object Name="CompositionContainerVisual" Inherits="CompositionVisual"/>
+    <Object Name="CompositionSolidColorVisual" Inherits="CompositionContainerVisual">
+        <Property Name="Color" Type="Avalonia.Media.Color" Animated="true" />
+    </Object>
     <List Name="CompositionVisualCollection" ItemType="CompositionVisual" CustomCtor="true"/>
     <Object Name="CompositionTarget" CustomServerCtor="true">
         <Property Name="Root" Type="CompositionVisual?"/>

src/Avalonia.Controls/Border.cs

@@ -4,6 +4,7 @@ using Avalonia.Controls.Shapes;
 using Avalonia.Controls.Utils;
 using Avalonia.Layout;
 using Avalonia.Media;
+using Avalonia.Rendering.Composition;
 using Avalonia.Utilities;
 using Avalonia.VisualTree;
 
@@ -73,6 +74,7 @@ namespace Avalonia.Controls
         private readonly BorderRenderHelper _borderRenderHelper = new BorderRenderHelper();
         private Thickness? _layoutThickness;
         private double _scale;
+        private CompositionBorderVisual? _borderVisual;
 
         /// <summary>
         /// Initializes static members of the <see cref="Border"/> class.
@@ -101,6 +103,10 @@ namespace Avalonia.Controls
                 case nameof(BorderThickness):
                     _layoutThickness = null;
                     break;
+                case nameof(CornerRadius):
+                    if (_borderVisual != null)
+                        _borderVisual.CornerRadius = CornerRadius;
+                    break;
             }
         }
 
@@ -245,6 +251,14 @@ namespace Avalonia.Controls
             return LayoutHelper.ArrangeChild(Child, finalSize, Padding, BorderThickness);
         }
 
+        private protected override CompositionDrawListVisual CreateCompositionVisual(Compositor compositor)
+        {
+            return _borderVisual = new CompositionBorderVisual(compositor, this)
+            {
+                CornerRadius = CornerRadius
+            };
+        }
+
         public CornerRadius ClipToBoundsRadius => CornerRadius;
     }
 }

src/Avalonia.Controls/BorderVisual.cs

@@ -0,0 +1,76 @@
+using System;
+using Avalonia.Rendering.Composition;
+using Avalonia.Rendering.Composition.Server;
+using Avalonia.Rendering.Composition.Transport;
+using Avalonia.Rendering.SceneGraph;
+
+namespace Avalonia.Controls;
+
+class CompositionBorderVisual : CompositionDrawListVisual
+{
+    private CornerRadius _cornerRadius;
+    private bool _cornerRadiusChanged;
+    
+    public CompositionBorderVisual(Compositor compositor, Visual visual) : base(compositor,
+        new ServerBorderVisual(compositor.Server, visual), visual)
+    {
+    }
+
+    public CornerRadius CornerRadius
+    {
+        get => _cornerRadius;
+        set
+        {
+            if (_cornerRadius != value)
+            {
+                _cornerRadiusChanged = true;
+                _cornerRadius = value;
+                RegisterForSerialization();
+            }
+        }
+    }
+
+    private protected override void SerializeChangesCore(BatchStreamWriter writer)
+    {
+        base.SerializeChangesCore(writer);
+        writer.Write(_cornerRadiusChanged);
+        if (_cornerRadiusChanged)
+            writer.Write(_cornerRadius);
+    }
+
+    class ServerBorderVisual : ServerCompositionDrawListVisual
+    {
+        private CornerRadius _cornerRadius;
+        public ServerBorderVisual(ServerCompositor compositor, Visual v) : base(compositor, v)
+        {
+        }
+
+        protected override void RenderCore(CompositorDrawingContextProxy canvas, Rect currentTransformedClip)
+        {
+            if (ClipToBounds)
+            {
+                var clipRect = Root!.SnapToDevicePixels(new Rect(new Size(Size.X, Size.Y)));
+                if (_cornerRadius.IsEmpty)
+                    canvas.PushClip(clipRect);
+                else
+                    canvas.PushClip(new RoundedRect(clipRect, _cornerRadius));
+            }
+
+            base.RenderCore(canvas, currentTransformedClip);
+            
+            if(ClipToBounds)
+                canvas.PopClip();
+            
+        }
+
+        protected override void DeserializeChangesCore(BatchStreamReader reader, TimeSpan commitedAt)
+        {
+            base.DeserializeChangesCore(reader, commitedAt);
+            if (reader.Read<bool>())
+                _cornerRadius = reader.Read<CornerRadius>();
+        }
+
+        protected override bool HandlesClipToBounds => true;
+    }
+
+}

src/Avalonia.Controls/Generators/IItemContainerGenerator.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using Avalonia.Controls.Templates;
+using Avalonia.Data;
 using Avalonia.Styling;
 
 namespace Avalonia.Controls.Generators
@@ -24,6 +25,11 @@ namespace Avalonia.Controls.Generators
         /// Gets or sets the data template used to display the items in the control.
         /// </summary>
         IDataTemplate? ItemTemplate { get; set; }
+        
+        /// <summary>
+        /// Gets or sets the binding to use to bind to the member of an item used for displaying
+        /// </summary>
+        IBinding? DisplayMemberBinding { get; set; }
 
         /// <summary>
         /// Gets the ContainerType, or null if its an untyped ContainerGenerator.

src/Avalonia.Controls/Generators/ItemContainerGenerator.cs

@@ -45,6 +45,9 @@ namespace Avalonia.Controls.Generators
         /// Gets or sets the data template used to display the items in the control.
         /// </summary>
         public IDataTemplate? ItemTemplate { get; set; }
+        
+        /// <inheritdoc />
+        public IBinding? DisplayMemberBinding { get; set; }
 
         /// <summary>
         /// Gets the owner control.
@@ -189,7 +192,15 @@ namespace Avalonia.Controls.Generators
             if (result == null)
             {
                 result = new ContentPresenter();
-                result.SetValue(ContentPresenter.ContentProperty, item, BindingPriority.Style);
+                if (DisplayMemberBinding is not null)
+                {
+                    result.SetValue(StyledElement.DataContextProperty, item, BindingPriority.Style);
+                    result.Bind(ContentPresenter.ContentProperty, DisplayMemberBinding, BindingPriority.Style);
+                }
+                else
+                {
+                    result.SetValue(ContentPresenter.ContentProperty, item, BindingPriority.Style);
+                }
 
                 if (ItemTemplate != null)
                 {

src/Avalonia.Controls/Generators/ItemContainerGenerator`1.cs

@@ -53,8 +53,16 @@ namespace Avalonia.Controls.Generators
                     container.SetValue(ContentTemplateProperty, ItemTemplate, BindingPriority.Style);
                 }
 
-                container.SetValue(ContentProperty, item, BindingPriority.Style);
+                if (DisplayMemberBinding is not null)
-
+                {
+                    container.SetValue(StyledElement.DataContextProperty, item, BindingPriority.Style);
+                    container.Bind(ContentProperty, DisplayMemberBinding, BindingPriority.Style);
+                }
+                else
+                {
+                    container.SetValue(ContentProperty, item, BindingPriority.Style);
+                }
+                
                 if (!(item is IControl))
                 {
                     container.DataContext = item;

src/Avalonia.Controls/Generators/TabItemContainerGenerator.cs

@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using Avalonia.Controls.Primitives;
 using Avalonia.Controls.Templates;
+using Avalonia.Data;
 using Avalonia.LogicalTree;
 using Avalonia.Reactive;
 using Avalonia.VisualTree;
@@ -33,6 +34,12 @@ namespace Avalonia.Controls.Generators
                     TabControl.ItemTemplateProperty));
             }
 
+            if (Owner.HeaderDisplayMemberBinding is not null)
+            {
+                tabItem.Bind(HeaderedContentControl.HeaderProperty, Owner.HeaderDisplayMemberBinding,
+                    BindingPriority.Style);
+            }
+
             if (tabItem.Header == null)
             {
                 if (item is IHeadered headered)

src/Avalonia.Controls/Generators/TreeItemContainerGenerator.cs

@@ -76,7 +76,15 @@ namespace Avalonia.Controls.Generators
                     result.SetValue(Control.ThemeProperty, ItemContainerTheme, BindingPriority.Style);
                 }
 
-                result.SetValue(ContentProperty, template.Build(item), BindingPriority.Style);
+                if (DisplayMemberBinding is not null)
+                {
+                    result.SetValue(StyledElement.DataContextProperty, item, BindingPriority.Style);
+                    result.Bind(ContentProperty, DisplayMemberBinding, BindingPriority.Style);
+                }
+                else
+                {
+                    result.SetValue(ContentProperty, template.Build(item), BindingPriority.Style);
+                }
 
                 var itemsSelector = template.ItemsSelector(item);
 

src/Avalonia.Controls/ItemsControl.cs

@@ -11,6 +11,7 @@ using Avalonia.Controls.Presenters;
 using Avalonia.Controls.Primitives;
 using Avalonia.Controls.Templates;
 using Avalonia.Controls.Utils;
+using Avalonia.Data;
 using Avalonia.Input;
 using Avalonia.LogicalTree;
 using Avalonia.Metadata;
@@ -61,6 +62,23 @@ namespace Avalonia.Controls
         public static readonly StyledProperty<IDataTemplate?> ItemTemplateProperty =
             AvaloniaProperty.Register<ItemsControl, IDataTemplate?>(nameof(ItemTemplate));
 
+
+        /// <summary>
+        /// Defines the <see cref="DisplayMemberBinding" /> property
+        /// </summary>
+        public static readonly StyledProperty<IBinding?> DisplayMemberBindingProperty =
+            AvaloniaProperty.Register<ItemsControl, IBinding?>(nameof(DisplayMemberBinding));
+
+        /// <summary>
+        /// Gets or sets the <see cref="IBinding"/> to use for binding to the display member of each item.
+        /// </summary>
+        [AssignBinding]
+        public IBinding? DisplayMemberBinding
+        {
+            get { return GetValue(DisplayMemberBindingProperty); }
+            set { SetValue(DisplayMemberBindingProperty, value); }
+        }
+        
         private IEnumerable? _items = new AvaloniaList<object>();
         private int _itemCount;
         private IItemContainerGenerator? _itemContainerGenerator;
@@ -97,6 +115,7 @@ namespace Avalonia.Controls
 
                     _itemContainerGenerator.ItemContainerTheme = ItemContainerTheme;
                     _itemContainerGenerator.ItemTemplate = ItemTemplate;
+                    _itemContainerGenerator.DisplayMemberBinding = DisplayMemberBinding;
                     _itemContainerGenerator.Materialized += (_, e) => OnContainersMaterialized(e);
                     _itemContainerGenerator.Dematerialized += (_, e) => OnContainersDematerialized(e);
                     _itemContainerGenerator.Recycled += (_, e) => OnContainersRecycled(e);

src/Avalonia.Controls/Presenters/ItemsPresenterBase.cs

@@ -5,6 +5,7 @@ using Avalonia.Collections;
 using Avalonia.Controls.Generators;
 using Avalonia.Controls.Templates;
 using Avalonia.Controls.Utils;
+using Avalonia.Data;
 using Avalonia.LogicalTree;
 using Avalonia.Styling;
 
@@ -33,6 +34,12 @@ namespace Avalonia.Controls.Presenters
         public static readonly StyledProperty<IDataTemplate?> ItemTemplateProperty =
             ItemsControl.ItemTemplateProperty.AddOwner<ItemsPresenterBase>();
 
+        /// <summary>
+        /// Defines the <see cref="DisplayMemberBinding" /> property
+        /// </summary>
+        public static readonly StyledProperty<IBinding?> DisplayMemberBindingProperty =
+            ItemsControl.DisplayMemberBindingProperty.AddOwner<ItemsPresenterBase>();
+        
         private IEnumerable? _items;
         private IDisposable? _itemsSubscription;
         private bool _createdPanel;
@@ -120,6 +127,15 @@ namespace Avalonia.Controls.Presenters
             set { SetValue(ItemTemplateProperty, value); }
         }
 
+        /// <summary>
+        /// Gets or sets the <see cref="IBinding"/> to use for binding to the display member of each item.
+        /// </summary>
+        public IBinding? DisplayMemberBinding
+        {
+            get { return GetValue(DisplayMemberBindingProperty); }
+            set { SetValue(DisplayMemberBindingProperty, value); }
+        }
+
         /// <summary>
         /// Gets the panel used to display the items.
         /// </summary>
@@ -177,6 +193,7 @@ namespace Avalonia.Controls.Presenters
             {
                 result = new ItemContainerGenerator(this);
                 result.ItemTemplate = ItemTemplate;
+                result.DisplayMemberBinding = DisplayMemberBinding;
             }
 
             result.Materialized += ContainerActionHandler;

src/Avalonia.Controls/TabControl.cs

@@ -12,6 +12,7 @@ using Avalonia.LogicalTree;
 using Avalonia.VisualTree;
 using Avalonia.Automation;
 using Avalonia.Controls.Metadata;
+using Avalonia.Data;
 
 namespace Avalonia.Controls
 {
@@ -57,6 +58,12 @@ namespace Avalonia.Controls
         public static readonly StyledProperty<IDataTemplate?> SelectedContentTemplateProperty =
             AvaloniaProperty.Register<TabControl, IDataTemplate?>(nameof(SelectedContentTemplate));
 
+        /// <summary>
+        /// Defines the <see cref="HeaderDisplayMemberBinding" /> property
+        /// </summary>
+        public static readonly StyledProperty<IBinding?> HeaderDisplayMemberBindingProperty =
+            AvaloniaProperty.Register<HeaderedItemsControl, IBinding?>(nameof(HeaderDisplayMemberBinding));
+        
         /// <summary>
         /// The default value for the <see cref="ItemsControl.ItemsPanel"/> property.
         /// </summary>
@@ -134,6 +141,16 @@ namespace Avalonia.Controls
             get { return GetValue(SelectedContentTemplateProperty); }
             internal set { SetValue(SelectedContentTemplateProperty, value); }
         }
+        
+        /// <summary>
+        /// Gets or sets the <see cref="IBinding"/> to use for binding to the display member of each tab-items header.
+        /// </summary>
+        [AssignBinding]
+        public IBinding? HeaderDisplayMemberBinding
+        {
+            get { return GetValue(HeaderDisplayMemberBindingProperty); }
+            set { SetValue(HeaderDisplayMemberBindingProperty, value); }
+        }
 
         internal ItemsPresenter? ItemsPresenterPart { get; private set; }
 

src/Avalonia.Controls/TextBox.cs

@@ -17,7 +17,6 @@ using Avalonia.Controls.Metadata;
 using Avalonia.Media.TextFormatting;
 using Avalonia.Media.TextFormatting.Unicode;
 using Avalonia.Automation.Peers;
-using System.Diagnostics;
 using Avalonia.Threading;
 
 namespace Avalonia.Controls
@@ -29,60 +28,108 @@ namespace Avalonia.Controls
     [PseudoClasses(":empty")]
     public class TextBox : TemplatedControl, UndoRedoHelper<TextBox.UndoRedoState>.IUndoRedoHost
     {
+        /// <summary>
+        /// Gets a platform-specific <see cref="KeyGesture"/> for the Cut action
+        /// </summary>
         public static KeyGesture? CutGesture { get; } = AvaloniaLocator.Current
             .GetService<PlatformHotkeyConfiguration>()?.Cut.FirstOrDefault();
 
+        /// <summary>
+        /// Gets a platform-specific <see cref="KeyGesture"/> for the Copy action
+        /// </summary>
         public static KeyGesture? CopyGesture { get; } = AvaloniaLocator.Current
             .GetService<PlatformHotkeyConfiguration>()?.Copy.FirstOrDefault();
 
+        /// <summary>
+        /// Gets a platform-specific <see cref="KeyGesture"/> for the Paste action
+        /// </summary>
         public static KeyGesture? PasteGesture { get; } = AvaloniaLocator.Current
             .GetService<PlatformHotkeyConfiguration>()?.Paste.FirstOrDefault();
 
+        /// <summary>
+        /// Defines the <see cref="AcceptsReturn"/> property
+        /// </summary>
         public static readonly StyledProperty<bool> AcceptsReturnProperty =
             AvaloniaProperty.Register<TextBox, bool>(nameof(AcceptsReturn));
 
+        /// <summary>
+        /// Defines the <see cref="AcceptsTab"/> property
+        /// </summary>
         public static readonly StyledProperty<bool> AcceptsTabProperty =
             AvaloniaProperty.Register<TextBox, bool>(nameof(AcceptsTab));
 
+        /// <summary>
+        /// Defines the <see cref="CaretIndex"/> property
+        /// </summary>
         public static readonly DirectProperty<TextBox, int> CaretIndexProperty =
             AvaloniaProperty.RegisterDirect<TextBox, int>(
                 nameof(CaretIndex),
                 o => o.CaretIndex,
                 (o, v) => o.CaretIndex = v);
 
+        /// <summary>
+        /// Defines the <see cref="IsReadOnly"/> property
+        /// </summary>
         public static readonly StyledProperty<bool> IsReadOnlyProperty =
             AvaloniaProperty.Register<TextBox, bool>(nameof(IsReadOnly));
 
+        /// <summary>
+        /// Defines the <see cref="PasswordChar"/> property
+        /// </summary>
         public static readonly StyledProperty<char> PasswordCharProperty =
             AvaloniaProperty.Register<TextBox, char>(nameof(PasswordChar));
 
+        /// <summary>
+        /// Defines the <see cref="SelectionBrush"/> property
+        /// </summary>
         public static readonly StyledProperty<IBrush?> SelectionBrushProperty =
             AvaloniaProperty.Register<TextBox, IBrush?>(nameof(SelectionBrush));
 
+        /// <summary>
+        /// Defines the <see cref="SelectionForegroundBrush"/> property
+        /// </summary>
         public static readonly StyledProperty<IBrush?> SelectionForegroundBrushProperty =
             AvaloniaProperty.Register<TextBox, IBrush?>(nameof(SelectionForegroundBrush));
 
+        /// <summary>
+        /// Defines the <see cref="CaretBrush"/> property
+        /// </summary>
         public static readonly StyledProperty<IBrush?> CaretBrushProperty =
             AvaloniaProperty.Register<TextBox, IBrush?>(nameof(CaretBrush));
 
+        /// <summary>
+        /// Defines the <see cref="SelectionStart"/> property
+        /// </summary>
         public static readonly DirectProperty<TextBox, int> SelectionStartProperty =
             AvaloniaProperty.RegisterDirect<TextBox, int>(
                 nameof(SelectionStart),
                 o => o.SelectionStart,
                 (o, v) => o.SelectionStart = v);
 
+        /// <summary>
+        /// Defines the <see cref="SelectionEnd"/> property
+        /// </summary>
         public static readonly DirectProperty<TextBox, int> SelectionEndProperty =
             AvaloniaProperty.RegisterDirect<TextBox, int>(
                 nameof(SelectionEnd),
                 o => o.SelectionEnd,
                 (o, v) => o.SelectionEnd = v);
 
+        /// <summary>
+        /// Defines the <see cref="MaxLength"/> property
+        /// </summary>
         public static readonly StyledProperty<int> MaxLengthProperty =
             AvaloniaProperty.Register<TextBox, int>(nameof(MaxLength), defaultValue: 0);
 
+        /// <summary>
+        /// Defines the <see cref="MaxLines"/> property
+        /// </summary>
         public static readonly StyledProperty<int> MaxLinesProperty =
             AvaloniaProperty.Register<TextBox, int>(nameof(MaxLines), defaultValue: 0);
 
+        /// <summary>
+        /// Defines the <see cref="Text"/> property
+        /// </summary>
         public static readonly DirectProperty<TextBox, string?> TextProperty =
             TextBlock.TextProperty.AddOwnerWithDataValidation<TextBox>(
                 o => o.Text,
@@ -90,6 +137,9 @@ namespace Avalonia.Controls
                 defaultBindingMode: BindingMode.TwoWay,
                 enableDataValidation: true);
 
+        /// <summary>
+        /// Defines the <see cref="TextAlignment"/> property
+        /// </summary>
         public static readonly StyledProperty<TextAlignment> TextAlignmentProperty =
             TextBlock.TextAlignmentProperty.AddOwner<TextBox>();
 
@@ -120,45 +170,78 @@ namespace Avalonia.Controls
         public static readonly StyledProperty<double> LetterSpacingProperty =
             TextBlock.LetterSpacingProperty.AddOwner<TextBox>();
 
+        /// <summary>
+        /// Defines the <see cref="Watermark"/> property
+        /// </summary>
         public static readonly StyledProperty<string?> WatermarkProperty =
             AvaloniaProperty.Register<TextBox, string?>(nameof(Watermark));
 
+        /// <summary>
+        /// Defines the <see cref="UseFloatingWatermark"/> property
+        /// </summary>
         public static readonly StyledProperty<bool> UseFloatingWatermarkProperty =
             AvaloniaProperty.Register<TextBox, bool>(nameof(UseFloatingWatermark));
 
+        /// <summary>
+        /// Defines the <see cref="NewLine"/> property
+        /// </summary>
         public static readonly DirectProperty<TextBox, string> NewLineProperty =
             AvaloniaProperty.RegisterDirect<TextBox, string>(nameof(NewLine),
                 textbox => textbox.NewLine, (textbox, newline) => textbox.NewLine = newline);
 
+        /// <summary>
+        /// Defines the <see cref="InnerLeftContent"/> property
+        /// </summary>
         public static readonly StyledProperty<object> InnerLeftContentProperty =
             AvaloniaProperty.Register<TextBox, object>(nameof(InnerLeftContent));
 
+        /// <summary>
+        /// Defines the <see cref="InnerRightContent"/> property
+        /// </summary>
         public static readonly StyledProperty<object> InnerRightContentProperty =
             AvaloniaProperty.Register<TextBox, object>(nameof(InnerRightContent));
 
+        /// <summary>
+        /// Defines the <see cref="RevealPassword"/> property
+        /// </summary>
         public static readonly StyledProperty<bool> RevealPasswordProperty =
             AvaloniaProperty.Register<TextBox, bool>(nameof(RevealPassword));
 
+        /// <summary>
+        /// Defines the <see cref="CanCut"/> property
+        /// </summary>
         public static readonly DirectProperty<TextBox, bool> CanCutProperty =
             AvaloniaProperty.RegisterDirect<TextBox, bool>(
                 nameof(CanCut),
                 o => o.CanCut);
 
+        /// <summary>
+        /// Defines the <see cref="CanCopy"/> property
+        /// </summary>
         public static readonly DirectProperty<TextBox, bool> CanCopyProperty =
             AvaloniaProperty.RegisterDirect<TextBox, bool>(
                 nameof(CanCopy),
                 o => o.CanCopy);
 
+        /// <summary>
+        /// Defines the <see cref="CanPaste"/> property
+        /// </summary>
         public static readonly DirectProperty<TextBox, bool> CanPasteProperty =
             AvaloniaProperty.RegisterDirect<TextBox, bool>(
                 nameof(CanPaste),
                 o => o.CanPaste);
 
+        /// <summary>
+        /// Defines the <see cref="IsUndoEnabled"/> property
+        /// </summary>
         public static readonly StyledProperty<bool> IsUndoEnabledProperty =
             AvaloniaProperty.Register<TextBox, bool>(
                 nameof(IsUndoEnabled),
                 defaultValue: true);
 
+        /// <summary>
+        /// Defines the <see cref="UndoLimit"/> property
+        /// </summary>
         public static readonly DirectProperty<TextBox, int> UndoLimitProperty =
             AvaloniaProperty.RegisterDirect<TextBox, int>(
                 nameof(UndoLimit),
@@ -166,6 +249,18 @@ namespace Avalonia.Controls
                 (o, v) => o.UndoLimit = v,
                 unsetValue: -1);
 
+        /// <summary>
+        /// Defines the <see cref="CanUndo"/> property
+        /// </summary>
+        public static readonly DirectProperty<TextBox, bool> CanUndoProperty =
+            AvaloniaProperty.RegisterDirect<TextBox, bool>(nameof(CanUndo), x => x.CanUndo);
+
+        /// <summary>
+        /// Defines the <see cref="CanRedo"/> property
+        /// </summary>
+        public static readonly DirectProperty<TextBox, bool> CanRedoProperty =
+            AvaloniaProperty.RegisterDirect<TextBox, bool>(nameof(CanRedo), x => x.CanRedo);
+
         /// <summary>
         /// Defines the <see cref="CopyingToClipboard"/> event.
         /// </summary>
@@ -201,9 +296,13 @@ namespace Avalonia.Controls
             RoutedEvent.Register<TextBox, TextChangingEventArgs>(
                 nameof(TextChanging), RoutingStrategies.Bubble);
 
+        /// <summary>
+        /// Stores the state information for available actions in the UndoRedoHelper
+        /// </summary>
         readonly struct UndoRedoState : IEquatable<UndoRedoState>
         {
             public string? Text { get; }
+
             public int CaretPosition { get; }
 
             public UndoRedoState(string? text, int caretPosition)
@@ -232,6 +331,8 @@ namespace Avalonia.Controls
         private bool _canPaste;
         private string _newLine = Environment.NewLine;
         private static readonly string[] invalidCharacters = new String[1] { "\u007f" };
+        private bool _canUndo;
+        private bool _canRedo;
 
         private int _wordSelectionStart = -1;
         private int _selectedTextChangesMadeSinceLastUndoSnapshot;
@@ -268,24 +369,34 @@ namespace Avalonia.Controls
                 ScrollViewer.HorizontalScrollBarVisibilityProperty,
                 horizontalScrollBarVisibility,
                 BindingPriority.Style);
+
             _undoRedoHelper = new UndoRedoHelper<UndoRedoState>(this);
             _selectedTextChangesMadeSinceLastUndoSnapshot = 0;
             _hasDoneSnapshotOnce = false;
             UpdatePseudoclasses();
         }
 
+        /// <summary>
+        /// Gets or sets a value that determines whether the TextBox allows and displays newline or return characters
+        /// </summary>
         public bool AcceptsReturn
         {
             get => GetValue(AcceptsReturnProperty);
             set => SetValue(AcceptsReturnProperty, value);
         }
 
+        /// <summary>
+        /// Gets or sets a value that determins whether the TextBox allows and displays tabs
+        /// </summary>
         public bool AcceptsTab
         {
             get => GetValue(AcceptsTabProperty);
             set => SetValue(AcceptsTabProperty, value);
         }
 
+        /// <summary>
+        /// Gets or sets the index of the text caret
+        /// </summary>
         public int CaretIndex
         {
             get => _caretIndex;
@@ -302,36 +413,54 @@ namespace Avalonia.Controls
             }
         }
 
+        /// <summary>
+        /// Gets or sets a value whether this TextBox is read-only
+        /// </summary>
         public bool IsReadOnly
         {
             get => GetValue(IsReadOnlyProperty);
             set => SetValue(IsReadOnlyProperty, value);
         }
 
+        /// <summary>
+        /// Gets or sets the <see cref="char"/> that should be used for password masking
+        /// </summary>
         public char PasswordChar
         {
             get => GetValue(PasswordCharProperty);
             set => SetValue(PasswordCharProperty, value);
         }
 
+        /// <summary>
+        /// Gets or sets a brush that is used to highlight selected text
+        /// </summary>
         public IBrush? SelectionBrush
         {
             get => GetValue(SelectionBrushProperty);
             set => SetValue(SelectionBrushProperty, value);
         }
 
+        /// <summary>
+        /// Gets or sets a brush that is used for the foreground of selected text
+        /// </summary>
         public IBrush? SelectionForegroundBrush
         {
             get => GetValue(SelectionForegroundBrushProperty);
             set => SetValue(SelectionForegroundBrushProperty, value);
         }
 
+        /// <summary>
+        /// Gets or sets a brush that is used for the text caret
+        /// </summary>
         public IBrush? CaretBrush
         {
             get => GetValue(CaretBrushProperty);
             set => SetValue(CaretBrushProperty, value);
         }
 
+        /// <summary>
+        /// Gets or sets the starting position of the text selected in the TextBox
+        /// </summary>
         public int SelectionStart
         {
             get => _selectionStart;
@@ -352,6 +481,13 @@ namespace Avalonia.Controls
             }
         }
 
+        /// <summary>
+        /// Gets or sets the end position of the text selected in the TextBox
+        /// </summary>
+        /// <remarks>
+        /// When the SelectionEnd is equal to <see cref="SelectionStart"/>, there is no 
+        /// selected text and it marks the caret position
+        /// </remarks>
         public int SelectionEnd
         {
             get => _selectionEnd;
@@ -371,19 +507,28 @@ namespace Avalonia.Controls
                 }
             }
         }
-
+        
+        /// <summary>
+        /// Gets or sets the maximum character length of the TextBox
+        /// </summary>
         public int MaxLength
         {
             get => GetValue(MaxLengthProperty);
             set => SetValue(MaxLengthProperty, value);
         }
 
+        /// <summary>
+        /// Gets or sets the maximum number of lines the TextBox can contain
+        /// </summary>
         public int MaxLines
         {
             get => GetValue(MaxLinesProperty);
             set => SetValue(MaxLinesProperty, value);
         }
 
+        /// <summary>
+        /// Gets or sets the spacing between characters
+        /// </summary>
         public double LetterSpacing
         {
             get => GetValue(LetterSpacingProperty);
@@ -399,6 +544,9 @@ namespace Avalonia.Controls
             set => SetValue(LineHeightProperty, value);
         }
 
+        /// <summary>
+        /// Gets or sets the Text content of the TextBox
+        /// </summary>
         [Content]
         public string? Text
         {
@@ -413,14 +561,20 @@ namespace Avalonia.Controls
                 SelectionStart = CoerceCaretIndex(selectionStart, value);
                 SelectionEnd = CoerceCaretIndex(selectionEnd, value);
 
-                var textChanged = SetAndRaise(TextProperty, ref _text, value);
+                // Before #9490, snapshot here was done AFTER text change - this doesn't make sense
-
+                // since intial state would never be no text and you'd always have to make a text 
-                if (textChanged && IsUndoEnabled && !_isUndoingRedoing)
+                // change before undo would be available
+                // The undo/redo stacks were also cleared at this point, which also doesn't make sense
+                // as it is still valid to want to undo a programmatic text set
+                // So we snapshot text now BEFORE the change so we can always revert
+                // Also don't need to check IsUndoEnabled here, that's done in SnapshotUndoRedo
+                if (!_isUndoingRedoing)
                 {
-                    _undoRedoHelper.Clear();
+                    SnapshotUndoRedo();
-                    SnapshotUndoRedo(); // so we always have an initial state
                 }
 
+                var textChanged = SetAndRaise(TextProperty, ref _text, value);
+
                 if (textChanged)
                 {
                     RaiseTextChangeEvents();
@@ -428,6 +582,9 @@ namespace Avalonia.Controls
             }
         }
 
+        /// <summary>
+        /// Gets or sets the text selected in the TextBox
+        /// </summary>
         public string SelectedText
         {
             get => GetSelection();
@@ -464,6 +621,9 @@ namespace Avalonia.Controls
             set => SetValue(VerticalContentAlignmentProperty, value);
         }
 
+        /// <summary>
+        /// Gets or sets the <see cref="Media.TextAlignment"/> of the TextBox
+        /// </summary>
         public TextAlignment TextAlignment
         {
             get => GetValue(TextAlignmentProperty);
@@ -490,24 +650,36 @@ namespace Avalonia.Controls
             set => SetValue(UseFloatingWatermarkProperty, value);
         }
 
+        /// <summary>
+        /// Gets or sets custom content that is positioned on the left side of the text layout box
+        /// </summary>
         public object InnerLeftContent
         {
             get => GetValue(InnerLeftContentProperty);
             set => SetValue(InnerLeftContentProperty, value);
         }
 
+        /// <summary>
+        /// Gets or sets custom content that is positioned on the right side of the text layout box
+        /// </summary>
         public object InnerRightContent
         {
             get => GetValue(InnerRightContentProperty);
             set => SetValue(InnerRightContentProperty, value);
         }
 
+        /// <summary>
+        /// Gets or sets whether text masked by <see cref="PasswordChar"/> should be revealed
+        /// </summary>
         public bool RevealPassword
         {
             get => GetValue(RevealPasswordProperty);
             set => SetValue(RevealPasswordProperty, value);
         }
 
+        /// <summary>
+        /// Gets or sets the <see cref="Media.TextWrapping"/> of the TextBox
+        /// </summary>
         public TextWrapping TextWrapping
         {
             get => GetValue(TextWrappingProperty);
@@ -567,6 +739,9 @@ namespace Avalonia.Controls
             set => SetValue(IsUndoEnabledProperty, value);
         }
 
+        /// <summary>
+        /// Gets or sets the maximum number of items that can reside in the Undo stack
+        /// </summary>
         public int UndoLimit
         {
             get => _undoRedoHelper.Limit;
@@ -590,18 +765,45 @@ namespace Avalonia.Controls
             }
         }
 
+        /// <summary>
+        /// Gets a value that indicates whether the undo stack has an action that can be undone
+        /// </summary>
+        public bool CanUndo
+        {
+            get => _canUndo;
+            private set => SetAndRaise(CanUndoProperty, ref _canUndo, value);
+        }
+
+        /// <summary>
+        /// Gets a value that indicates whether the redo stack has an action that can be redone
+        /// </summary>
+        public bool CanRedo
+        {
+            get => _canRedo;
+            private set => SetAndRaise(CanRedoProperty, ref _canRedo, value);
+        }
+
+        /// <summary>
+        /// Raised when content is being copied to the clipboard
+        /// </summary>
         public event EventHandler<RoutedEventArgs>? CopyingToClipboard
         {
             add => AddHandler(CopyingToClipboardEvent, value);
             remove => RemoveHandler(CopyingToClipboardEvent, value);
         }
 
+        /// <summary>
+        /// Raised when content is being cut to the clipboard
+        /// </summary>
         public event EventHandler<RoutedEventArgs>? CuttingToClipboard
         {
             add => AddHandler(CuttingToClipboardEvent, value);
             remove => RemoveHandler(CuttingToClipboardEvent, value);
         }
 
+        /// <summary>
+        /// Raised when content is being pasted from the clipboard
+        /// </summary>
         public event EventHandler<RoutedEventArgs>? PastingFromClipboard
         {
             add => AddHandler(PastingFromClipboardEvent, value);
@@ -831,6 +1033,9 @@ namespace Avalonia.Controls
             return text;
         }
 
+        /// <summary>
+        /// Cuts the current text onto the clipboard
+        /// </summary>
         public async void Cut()
         {
             var text = GetSelection();
@@ -851,6 +1056,9 @@ namespace Avalonia.Controls
             }
         }
 
+        /// <summary>
+        /// Copies the current text onto the clipboard
+        /// </summary>
         public async void Copy()
         {
             var text = GetSelection();
@@ -869,6 +1077,9 @@ namespace Avalonia.Controls
             }
         }
 
+        /// <summary>
+        /// Pastes the current clipboard text content into the TextBox
+        /// </summary>
         public async void Paste()
         {
             var eventArgs = new RoutedEventArgs(PastingFromClipboardEvent);
@@ -943,30 +1154,13 @@ namespace Avalonia.Controls
             }
             else if (Match(keymap.Undo) && IsUndoEnabled)
             {
-                try
+                Undo();
-                {
-                    SnapshotUndoRedo();
-                    _isUndoingRedoing = true;
-                    _undoRedoHelper.Undo();
-                }
-                finally
-                {
-                    _isUndoingRedoing = false;
-                }
 
                 handled = true;
             }
             else if (Match(keymap.Redo) && IsUndoEnabled)
             {
-                try
+                Redo();
-                {
-                    _isUndoingRedoing = true;
-                    _undoRedoHelper.Redo();
-                }
-                finally
-                {
-                    _isUndoingRedoing = false;
-                }
 
                 handled = true;
             }
@@ -1420,6 +1614,9 @@ namespace Avalonia.Controls
             }
         }
 
+        /// <summary>
+        /// Clears the text in the TextBox
+        /// </summary>
         public void Clear()
         {
             Text = string.Empty;
@@ -1703,5 +1900,62 @@ namespace Avalonia.Controls
                 }
             }
         }
+
+        /// <summary>
+        /// Undoes the first action in the undo stack
+        /// </summary>
+        public void Undo()
+        {
+            if (IsUndoEnabled && CanUndo)
+            {
+                try
+                {
+                    // Snapshot the current Text state - this will get popped on to the redo stack
+                    // when we call undo below
+                    SnapshotUndoRedo();
+                    _isUndoingRedoing = true;
+                    _undoRedoHelper.Undo();
+                }
+                finally
+                {
+                    _isUndoingRedoing = false;
+                }
+            }
+        }
+
+        /// <summary>
+        /// Reapplies the first item on the redo stack
+        /// </summary>
+        public void Redo()
+        {
+            if (IsUndoEnabled && CanRedo)
+            {
+                try
+                {
+                    _isUndoingRedoing = true;
+                    _undoRedoHelper.Redo();
+                }
+                finally
+                {
+                    _isUndoingRedoing = false;
+                }
+            }
+        }
+
+        /// <summary>
+        /// Called from the UndoRedoHelper when the undo stack is modified
+        /// </summary>
+        void UndoRedoHelper<UndoRedoState>.IUndoRedoHost.OnUndoStackChanged()
+        {
+            CanUndo = _undoRedoHelper.CanUndo;
+        }
+
+        /// <summary>
+        /// Called from the UndoRedoHelper when the redo stack is modified
+        /// </summary>
+        void UndoRedoHelper<UndoRedoState>.IUndoRedoHost.OnRedoStackChanged()
+        {
+            CanRedo = _undoRedoHelper.CanRedo;
+        }
     }
 }

src/Avalonia.Controls/Utils/UndoRedoHelper.cs

@@ -1,9 +1,4 @@
-using System;
 using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-using Avalonia.Utilities;
 
 namespace Avalonia.Controls.Utils
 {
@@ -14,9 +9,11 @@ namespace Avalonia.Controls.Utils
         public interface IUndoRedoHost
         {
             TState UndoRedoState { get; set; }
-        }
 
+            void OnUndoStackChanged();
 
+            void OnRedoStackChanged();
+        }
 
         private readonly LinkedList<TState> _states = new LinkedList<TState>();
 
@@ -28,6 +25,10 @@ namespace Avalonia.Controls.Utils
         /// </summary>
         public int Limit { get; set; } = 10;
 
+        public bool CanUndo => _currentNode?.Previous != null;
+
+        public bool CanRedo => _currentNode?.Next != null;
+
         public UndoRedoHelper(IUndoRedoHost host)
         {
             _host = host;
@@ -39,6 +40,8 @@ namespace Avalonia.Controls.Utils
             {
                 _currentNode = _currentNode.Previous;
                 _host.UndoRedoState = _currentNode.Value;
+                _host.OnUndoStackChanged();
+                _host.OnRedoStackChanged();
             }
         }
 
@@ -55,6 +58,7 @@ namespace Avalonia.Controls.Utils
         }
 
         public bool HasState => _currentNode != null;
+
         public void UpdateLastState(TState state)
         {
             if (_states.Last != null)
@@ -72,6 +76,8 @@ namespace Avalonia.Controls.Utils
         {
             while (_currentNode?.Next != null)
                 _states.Remove(_currentNode.Next);
+
+            _host.OnRedoStackChanged();
         }
 
         public void Redo()
@@ -80,6 +86,8 @@ namespace Avalonia.Controls.Utils
             {
                 _currentNode = _currentNode.Next;
                 _host.UndoRedoState = _currentNode.Value;
+                _host.OnRedoStackChanged();
+                _host.OnUndoStackChanged();
             }
         }
 
@@ -94,6 +102,9 @@ namespace Avalonia.Controls.Utils
                 _currentNode = _states.Last;
                 if (Limit != -1 && _states.Count > Limit)
                     _states.RemoveFirst();
+
+                _host.OnUndoStackChanged();
+                _host.OnRedoStackChanged();
             }
         }
 
@@ -101,6 +112,9 @@ namespace Avalonia.Controls.Utils
         {
             _states.Clear();
             _currentNode = null;
+
+            _host.OnUndoStackChanged();
+            _host.OnRedoStackChanged();
         }
     }
 }

tests/Avalonia.Controls.UnitTests/ItemsControlTests.cs

@@ -4,6 +4,7 @@ using System.Linq;
 using Avalonia.Collections;
 using Avalonia.Controls.Presenters;
 using Avalonia.Controls.Templates;
+using Avalonia.Data;
 using Avalonia.Input;
 using Avalonia.LogicalTree;
 using Avalonia.Styling;
@@ -736,6 +737,25 @@ namespace Avalonia.Controls.UnitTests
             root.Child = null;
             root.Child = target;
         }
+        
+        [Fact]
+        public void Should_Use_DisplayMemberBinding()
+        {
+            var target = new ItemsControl
+            {
+                Template = GetTemplate(),
+                DisplayMemberBinding = new Binding("Length")
+            };
+
+            target.Items = new[] { "Foo" };
+            target.ApplyTemplate();
+            target.Presenter.ApplyTemplate();
+
+            var container = (ContentPresenter)target.Presenter.Panel.Children[0];
+            container.UpdateChild();
+
+            Assert.Equal(container.Child!.GetValue(TextBlock.TextProperty), "3");
+        }
 
         private class Item
         {

tests/Avalonia.Controls.UnitTests/TextBoxTests.cs

@@ -866,6 +866,176 @@ namespace Avalonia.Controls.UnitTests
             }
         }
 
+        [Fact]
+        public void CanUndo_CanRedo_Is_False_When_Initialized()
+        {
+            using (UnitTestApplication.Start(Services))
+            {
+                var tb = new TextBox
+                {
+                    Template = CreateTemplate(),
+                    Text = "New Text"
+                };
+
+                tb.Measure(Size.Infinity);
+
+                Assert.False(tb.CanUndo);
+                Assert.False(tb.CanRedo);
+            }
+        }
+
+        [Fact]
+        public void CanUndo_CanRedo_and_Programmatic_Undo_Redo_Works()
+        {
+            using (UnitTestApplication.Start(Services))
+            {
+                var tb = new TextBox
+                {
+                    Template = CreateTemplate(),
+                };
+
+                tb.Measure(Size.Infinity);
+
+                // See GH #6024 for a bit more insight on when Undo/Redo snapshots are taken:
+                // - Every 'Space', but only when space is handled in OnKeyDown - Spaces in TextInput event won't work
+                // - Every 7 chars in a long word
+                RaiseTextEvent(tb, "ABC");
+                RaiseKeyEvent(tb, Key.Space, KeyModifiers.None);
+                RaiseTextEvent(tb, "DEF");
+                RaiseKeyEvent(tb, Key.Space, KeyModifiers.None);
+                RaiseTextEvent(tb, "123");
+
+                // NOTE: the spaces won't actually add spaces b/c they're sent only as key events and not Text events
+                //       so our final text is without spaces
+                Assert.Equal("ABCDEF123", tb.Text);
+
+                Assert.True(tb.CanUndo);
+
+                tb.Undo();
+
+                // Undo will take us back one step
+                Assert.Equal("ABCDEF", tb.Text);
+
+                Assert.True(tb.CanRedo);
+
+                tb.Redo();
+
+                // Redo should restore us
+                Assert.Equal("ABCDEF123", tb.Text);
+            }
+        }
+
+        [Fact]
+        public void Setting_UndoLimit_Clears_Undo_Redo()
+        {
+            using (UnitTestApplication.Start(Services))
+            {
+                var tb = new TextBox
+                {
+                    Template = CreateTemplate(),
+                };
+
+                tb.Measure(Size.Infinity);
+
+                // This is all the same as the above test (CanUndo_CanRedo_and_Programmatic_Undo_Redo_Works)
+                // We do this to get the undo/redo stacks in a state where both are active
+                RaiseTextEvent(tb, "ABC");
+                RaiseKeyEvent(tb, Key.Space, KeyModifiers.None);
+                RaiseTextEvent(tb, "DEF");
+                RaiseKeyEvent(tb, Key.Space, KeyModifiers.None);
+                RaiseTextEvent(tb, "123");
+
+                Assert.Equal("ABCDEF123", tb.Text);
+                Assert.True(tb.CanUndo);
+                tb.Undo();
+                // Undo will take us back one step
+                Assert.Equal("ABCDEF", tb.Text);
+                Assert.True(tb.CanRedo);
+                tb.Redo();
+                // Redo should restore us
+                Assert.Equal("ABCDEF123", tb.Text);
+
+                // Change the undo limit, this should clear both stacks setting CanUndo and CanRedo to false
+                tb.UndoLimit = 1;
+
+                Assert.False(tb.CanUndo);
+                Assert.False(tb.CanRedo);
+            }
+        }
+
+        [Fact]
+        public void Setting_IsUndoEnabled_To_False_Clears_Undo_Redo()
+        {
+            using (UnitTestApplication.Start(Services))
+            {
+                var tb = new TextBox
+                {
+                    Template = CreateTemplate(),
+                };
+
+                tb.Measure(Size.Infinity);
+
+                // This is all the same as the above test (CanUndo_CanRedo_and_Programmatic_Undo_Redo_Works)
+                // We do this to get the undo/redo stacks in a state where both are active
+                RaiseTextEvent(tb, "ABC");
+                RaiseKeyEvent(tb, Key.Space, KeyModifiers.None);
+                RaiseTextEvent(tb, "DEF");
+                RaiseKeyEvent(tb, Key.Space, KeyModifiers.None);
+                RaiseTextEvent(tb, "123");
+
+                Assert.Equal("ABCDEF123", tb.Text);
+                Assert.True(tb.CanUndo);
+                tb.Undo();
+                // Undo will take us back one step
+                Assert.Equal("ABCDEF", tb.Text);
+                Assert.True(tb.CanRedo);
+                tb.Redo();
+                // Redo should restore us
+                Assert.Equal("ABCDEF123", tb.Text);
+
+                // Disable Undo/Redo, this should clear both stacks setting CanUndo and CanRedo to false
+                tb.IsUndoEnabled = false;
+
+                Assert.False(tb.CanUndo);
+                Assert.False(tb.CanRedo);
+            }
+        }
+
+        [Fact]
+        public void UndoLimit_Count_Is_Respected()
+        {
+            using (UnitTestApplication.Start(Services))
+            {
+                var tb = new TextBox
+                {
+                    Template = CreateTemplate(),
+                    UndoLimit = 3 // Something small for this test
+                };
+
+                tb.Measure(Size.Infinity);
+
+                // Push 3 undoable actions, we should only be able to recover 2
+                RaiseTextEvent(tb, "ABC");
+                RaiseKeyEvent(tb, Key.Space, KeyModifiers.None);
+                RaiseTextEvent(tb, "DEF");
+                RaiseKeyEvent(tb, Key.Space, KeyModifiers.None);
+                RaiseTextEvent(tb, "123");
+
+                Assert.Equal("ABCDEF123", tb.Text);
+
+                // Undo will take us back one step
+                tb.Undo();                
+                Assert.Equal("ABCDEF", tb.Text);
+
+                // Undo again
+                tb.Undo();
+                Assert.Equal("ABC", tb.Text);
+
+                // We now should not be able to undo again
+                Assert.False(tb.CanUndo);
+            }
+        }
+
         private static TestServices FocusServices => TestServices.MockThreadingInterface.With(
             focusManager: new FocusManager(),
             keyboardDevice: () => new KeyboardDevice(),