AutoCompleteBox.Items -> ItemsSource.

samples/ControlCatalog/Pages/AutoCompleteBoxPage.xaml.cs

@@ -114,7 +114,7 @@ namespace ControlCatalog.Pages
 
             foreach (AutoCompleteBox box in GetAllAutoCompleteBox().Where(x => x.Name != "CustomAutocompleteBox"))
             {
-                box.Items = States;
+                box.ItemsSource = States;
             }
 
             var converter = new FuncMultiValueConverter<string, string>(parts =>
@@ -132,7 +132,7 @@ namespace ControlCatalog.Pages
             asyncBox.AsyncPopulator = PopulateAsync;
 
             var customAutocompleteBox = this.Get<AutoCompleteBox>("CustomAutocompleteBox");
-            customAutocompleteBox.Items = Sentences.SelectMany(x => x);
+            customAutocompleteBox.ItemsSource = Sentences.SelectMany(x => x);
             customAutocompleteBox.TextFilter = LastWordContains;
             customAutocompleteBox.TextSelector = AppendWord;
         }

samples/ControlCatalog/Pages/DialogsPage.xaml

@@ -45,7 +45,7 @@
     </Expander>
 
     <AutoCompleteBox x:Name="CurrentFolderBox" Watermark="Write full path/uri or well known folder name">
-      <AutoCompleteBox.Items>
+      <AutoCompleteBox.ItemsSource>
         <generic:List x:TypeArguments="storage:WellKnownFolder">
           <storage:WellKnownFolder>Desktop</storage:WellKnownFolder>
           <storage:WellKnownFolder>Documents</storage:WellKnownFolder>
@@ -54,7 +54,7 @@
           <storage:WellKnownFolder>Videos</storage:WellKnownFolder>
           <storage:WellKnownFolder>Music</storage:WellKnownFolder>
         </generic:List>
-      </AutoCompleteBox.Items>
+      </AutoCompleteBox.ItemsSource>
     </AutoCompleteBox>
     
     <TextBlock x:Name="PickerLastResultsVisible"

src/Avalonia.Controls/AutoCompleteBox/AutoCompleteBox.Properties.cs

@@ -143,12 +143,12 @@ namespace Avalonia.Controls
                 nameof(TextSelector));
 
         /// <summary>
-        /// Identifies the <see cref="Items" /> property.
+        /// Identifies the <see cref="ItemsSource" /> property.
         /// </summary>
-        /// <value>The identifier for the <see cref="Items" /> property.</value>
+        /// <value>The identifier for the <see cref="ItemsSource" /> property.</value>
-        public static readonly StyledProperty<IEnumerable?> ItemsProperty =
+        public static readonly StyledProperty<IEnumerable?> ItemsSourceProperty =
             AvaloniaProperty.Register<AutoCompleteBox, IEnumerable?>(
-                nameof(Items));
+                nameof(ItemsSource));
 
         /// <summary>
         /// Identifies the <see cref="AsyncPopulator" /> property.
@@ -311,10 +311,10 @@ namespace Avalonia.Controls
 
         /// <summary>
         /// Gets the text that is used to filter items in the
-        /// <see cref="Items" /> item collection.
+        /// <see cref="ItemsSource" /> item collection.
         /// </summary>
         /// <value>The text that is used to filter items in the
-        /// <see cref="Items" /> item collection.</value>
+        /// <see cref="ItemsSource" /> item collection.</value>
         /// <remarks>
         /// The SearchText value is typically the same as the
         /// Text property, but is set after the TextChanged event occurs
@@ -339,7 +339,7 @@ namespace Avalonia.Controls
 
         /// <summary>
         /// Gets or sets how the text in the text box is used to filter items
-        /// specified by the <see cref="Items" />
+        /// specified by the <see cref="ItemsSource" />
         /// property for display in the drop-down.
         /// </summary>
         /// <value>One of the <see cref="AutoCompleteFilterMode" />
@@ -366,11 +366,11 @@ namespace Avalonia.Controls
 
         /// <summary>
         /// Gets or sets the custom method that uses user-entered text to filter
-        /// the items specified by the <see cref="Items" />
+        /// the items specified by the <see cref="ItemsSource" />
         /// property for display in the drop-down.
         /// </summary>
         /// <value>The custom method that uses the user-entered text to filter
-        /// the items specified by the <see cref="Items" />
+        /// the items specified by the <see cref="ItemsSource" />
         /// property. The default is null.</value>
         /// <remarks>
         /// The filter mode is automatically set to Custom if you set the
@@ -384,11 +384,11 @@ namespace Avalonia.Controls
 
         /// <summary>
         /// Gets or sets the custom method that uses the user-entered text to
-        /// filter items specified by the <see cref="Items" />
+        /// filter items specified by the <see cref="ItemsSource" />
         /// property in a text-based way for display in the drop-down.
         /// </summary>
         /// <value>The custom method that uses the user-entered text to filter
-        /// items specified by the <see cref="Items" />
+        /// items specified by the <see cref="ItemsSource" />
         /// property in a text-based way for display in the drop-down.</value>
         /// <remarks>
         /// The search mode is automatically set to Custom if you set the
@@ -402,11 +402,11 @@ namespace Avalonia.Controls
 
         /// <summary>
         /// Gets or sets the custom method that combines the user-entered
-        /// text and one of the items specified by the <see cref="Items" />.
+        /// text and one of the items specified by the <see cref="ItemsSource" />.
         /// </summary>
         /// <value>
         /// The custom method that combines the user-entered
-        /// text and one of the items specified by the <see cref="Items" />.
+        /// text and one of the items specified by the <see cref="ItemsSource" />.
         /// </value>
         public AutoCompleteSelector<object>? ItemSelector
         {
@@ -417,11 +417,11 @@ namespace Avalonia.Controls
         /// <summary>
         /// Gets or sets the custom method that combines the user-entered
         /// text and one of the items specified by the
-        /// <see cref="Items" /> in a text-based way.
+        /// <see cref="ItemsSource" /> in a text-based way.
         /// </summary>
         /// <value>
         /// The custom method that combines the user-entered
-        /// text and one of the items specified by the <see cref="Items" />
+        /// text and one of the items specified by the <see cref="ItemsSource" />
         /// in a text-based way.
         /// </value>
         public AutoCompleteSelector<string?>? TextSelector
@@ -442,10 +442,10 @@ namespace Avalonia.Controls
         /// </summary>
         /// <value>The collection that is used to generate the items of the
         /// drop-down portion of the <see cref="AutoCompleteBox" /> control.</value>
-        public IEnumerable? Items
+        public IEnumerable? ItemsSource
         {
-            get => GetValue(ItemsProperty);
+            get => GetValue(ItemsSourceProperty);
-            set => SetValue(ItemsProperty, value);
+            set => SetValue(ItemsSourceProperty, value);
         }
     }
 }

src/Avalonia.Controls/AutoCompleteBox/AutoCompleteBox.cs

@@ -419,9 +419,9 @@ namespace Avalonia.Controls
         /// ItemsSourceProperty property changed handler.
         /// </summary>
         /// <param name="e">Event arguments.</param>
-        private void OnItemsPropertyChanged(AvaloniaPropertyChangedEventArgs e)
+        private void OnItemsSourcePropertyChanged(AvaloniaPropertyChangedEventArgs e)
         {
-            OnItemsChanged((IEnumerable?)e.NewValue);
+            OnItemsSourceChanged((IEnumerable?)e.NewValue);
         }
 
         private void OnItemTemplatePropertyChanged(AvaloniaPropertyChangedEventArgs e)
@@ -461,7 +461,7 @@ namespace Avalonia.Controls
             SearchTextProperty.Changed.AddClassHandler<AutoCompleteBox>((x,e) => x.OnSearchTextPropertyChanged(e));
             FilterModeProperty.Changed.AddClassHandler<AutoCompleteBox>((x,e) => x.OnFilterModePropertyChanged(e));
             ItemFilterProperty.Changed.AddClassHandler<AutoCompleteBox>((x,e) => x.OnItemFilterPropertyChanged(e));
-            ItemsProperty.Changed.AddClassHandler<AutoCompleteBox>((x,e) => x.OnItemsPropertyChanged(e));
+            ItemsSourceProperty.Changed.AddClassHandler<AutoCompleteBox>((x,e) => x.OnItemsSourcePropertyChanged(e));
             ItemTemplateProperty.Changed.AddClassHandler<AutoCompleteBox>((x,e) => x.OnItemTemplatePropertyChanged(e));
             IsEnabledProperty.Changed.AddClassHandler<AutoCompleteBox>((x,e) => x.OnControlIsEnabledChanged(e));
         }
@@ -559,7 +559,7 @@ namespace Avalonia.Controls
                     _adapter.Commit -= OnAdapterSelectionComplete;
                     _adapter.Cancel -= OnAdapterSelectionCanceled;
                     _adapter.Cancel -= OnAdapterSelectionComplete;
-                    _adapter.Items = null;
+                    _adapter.ItemsSource = null;
                 }
 
                 _adapter = value;
@@ -570,7 +570,7 @@ namespace Avalonia.Controls
                     _adapter.Commit += OnAdapterSelectionComplete;
                     _adapter.Cancel += OnAdapterSelectionCanceled;
                     _adapter.Cancel += OnAdapterSelectionComplete;
-                    _adapter.Items = _view;
+                    _adapter.ItemsSource = _view;
                 }
             }
         }
@@ -1128,7 +1128,7 @@ namespace Avalonia.Controls
                 {
                     if (!cancellationToken.IsCancellationRequested)
                     {
-                        SetCurrentValue(ItemsProperty, resultList);
+                        SetCurrentValue(ItemsSourceProperty, resultList);
                         PopulateComplete();
                     }
                 });
@@ -1475,7 +1475,7 @@ namespace Avalonia.Controls
         /// adapter's ItemsSource to the view if appropriate.
         /// </summary>
         /// <param name="newValue">The new enumerable reference.</param>
-        private void OnItemsChanged(IEnumerable? newValue)
+        private void OnItemsSourceChanged(IEnumerable? newValue)
         {
             // Remove handler for oldValue.CollectionChanged (if present)
             _collectionChangeSubscription?.Dispose();
@@ -1492,9 +1492,9 @@ namespace Avalonia.Controls
 
             // Clear and set the view on the selection adapter
             ClearView();
-            if (SelectionAdapter != null && SelectionAdapter.Items != _view)
+            if (SelectionAdapter != null && SelectionAdapter.ItemsSource != _view)
             {
-                SelectionAdapter.Items = _view;
+                SelectionAdapter.ItemsSource = _view;
             }
             if (IsDropDownOpen)
             {
@@ -1545,9 +1545,9 @@ namespace Avalonia.Controls
             {
                 // Significant changes to the underlying data.
                 ClearView();
-                if (Items != null)
+                if (ItemsSource != null)
                 {
-                    _items = new List<object>(Items.Cast<object>());
+                    _items = new List<object>(ItemsSource.Cast<object>());
                 }
             }
 
@@ -1582,9 +1582,9 @@ namespace Avalonia.Controls
             PopulatedEventArgs populated = new PopulatedEventArgs(new ReadOnlyCollection<object>(_view!));
             OnPopulated(populated);
 
-            if (SelectionAdapter != null && SelectionAdapter.Items != _view)
+            if (SelectionAdapter != null && SelectionAdapter.ItemsSource != _view)
             {
-                SelectionAdapter.Items = _view;
+                SelectionAdapter.ItemsSource = _view;
             }
 
             bool isDropDownOpen = _userCalledPopulate && (_view!.Count > 0);

src/Avalonia.Controls/Utils/ISelectionAdapter.cs

@@ -36,7 +36,7 @@ namespace Avalonia.Controls.Utils
         /// </summary>
         /// <value>The collection that is used to generate content for the
         /// selection adapter.</value>
-        IEnumerable? Items { get; set; }
+        IEnumerable? ItemsSource { get; set; }
 
         /// <summary>
         /// Occurs when a selected item is not cancelled and is committed as the

src/Avalonia.Controls/Utils/SelectingItemsControlSelectionAdapter.cs

@@ -140,7 +140,7 @@ namespace Avalonia.Controls.Utils
         /// </summary>
         /// <value>The collection used to generate content for the selection
         /// adapter.</value>
-        public IEnumerable? Items
+        public IEnumerable? ItemsSource
         {
             get
             {

tests/Avalonia.Controls.UnitTests/AutoCompleteBoxTests.cs

@@ -89,7 +89,7 @@ namespace Avalonia.Controls.UnitTests
                 bool closeEvent = false;
                 control.DropDownOpened += (s, e) => openEvent = true;
                 control.DropDownClosed += (s, e) => closeEvent = true;
-                control.Items = CreateSimpleStringArray();
+                control.ItemsSource = CreateSimpleStringArray();
 
                 textbox.Text = "a";
                 Dispatcher.UIThread.RunJobs();
@@ -258,7 +258,7 @@ namespace Avalonia.Controls.UnitTests
                 control.FilterMode = AutoCompleteFilterMode.None;
                 control.Populating += (s, e) =>
                 {
-                    control.Items = new string[] { custom };
+                    control.ItemsSource = new string[] { custom };
                     Assert.Equal(search, e.Parameter);
                 };
                 control.Populated += (s, e) =>
@@ -380,7 +380,7 @@ namespace Avalonia.Controls.UnitTests
         {
             RunTest((control, textbox) =>
             {
-                object selectedItem = control.Items.Cast<object>().First();
+                object selectedItem = control.ItemsSource.Cast<object>().First();
                 string input = "42";
 
                 control.TextSelector = (text, item) => text + item;
@@ -397,7 +397,7 @@ namespace Avalonia.Controls.UnitTests
         {
             RunTest((control, textbox) =>
             {
-                object selectedItem = control.Items.Cast<object>().First();
+                object selectedItem = control.ItemsSource.Cast<object>().First();
                 string input = "42";
 
                 control.ItemSelector = (text, item) => text + item;
@@ -1053,7 +1053,7 @@ namespace Avalonia.Controls.UnitTests
             using (UnitTestApplication.Start(Services))
             {
                 AutoCompleteBox control = CreateControl();
-                control.Items = CreateSimpleStringArray();
+                control.ItemsSource = CreateSimpleStringArray();
                 TextBox textBox = GetTextBox(control);
                 var window = new Window {Content = control};
                 window.ApplyStyling();