Added automation peer class for carousel and item

Microsoft.Toolkit.Uwp.UI.Controls/Carousel/Carousel.cs

@@ -10,6 +10,7 @@
 using Windows.Foundation;
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Automation;
+using Windows.UI.Xaml.Automation.Peers;
 using Windows.UI.Xaml.Controls;
 using Windows.UI.Xaml.Input;
 using Windows.UI.Xaml.Media;
@@ -522,6 +523,17 @@ protected override void PrepareContainerForItemOverride(DependencyObject element
             {
                 carouselItem.IsSelected = true;
             }
+
+            carouselItem.ParentCarousel = this;
+        }
+
+        /// <summary>
+        /// Creates AutomationPeer (<see cref="UIElement.OnCreateAutomationPeer"/>)
+        /// </summary>
+        /// <returns>An automation peer for this <see cref="Carousel"/>.</returns>
+        protected override AutomationPeer OnCreateAutomationPeer()
+        {
+            return new CarouselAutomationPeer(this);
         }
 
         private void OnCarouselItemSelected(object sender, EventArgs e)
@@ -530,5 +542,19 @@ private void OnCarouselItemSelected(object sender, EventArgs e)
 
             SelectedItem = ItemFromContainer(item);
         }
+
+        internal IEnumerable<CarouselItem> GetCarouselItems()
+        {
+            return Enumerable
+                .Range(0, Items.Count)
+                .Select(idx => (CarouselItem)ContainerFromIndex(idx))
+                .Where(i => i != null);
+        }
+
+        internal void SetSelectedItem(CarouselItem owner)
+        {
+            var item = ItemFromContainer(owner);
+            SelectedItem = item;
+        }
     }
 }

Microsoft.Toolkit.Uwp.UI.Controls/Carousel/CarouselAutomationPeer.cs

@@ -0,0 +1,147 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Collections.Generic;
+using System.Linq;
+using Windows.UI.Xaml.Automation.Peers;
+using Windows.UI.Xaml.Automation.Provider;
+using Windows.UI.Xaml.Controls;
+
+namespace Microsoft.Toolkit.Uwp.UI.Controls
+{
+    /// <summary>
+    /// Defines a framework element automation peer for the <see cref="Carousel"/> control.
+    /// </summary>
+    public class CarouselAutomationPeer : ItemsControlAutomationPeer, ISelectionProvider
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="CarouselAutomationPeer"/> class.
+        /// </summary>
+        /// <param name="owner">
+        /// The <see cref="Carousel" /> that is associated with this <see cref="T:Windows.UI.Xaml.Automation.Peers.CarouselAutomationPeer" />.
+        /// </param>
+        public CarouselAutomationPeer(Carousel owner)
+            : base(owner)
+        {
+        }
+
+        /// <summary>Gets a value indicating whether the Microsoft UI Automation provider allows more than one child element to be selected concurrently.</summary>
+        /// <returns>True if multiple selection is allowed; otherwise, false.</returns>
+        public bool CanSelectMultiple => false;
+
+        /// <summary>Gets a value indicating whether the UI Automation provider requires at least one child element to be selected.</summary>
+        /// <returns>True if selection is required; otherwise, false.</returns>
+        public bool IsSelectionRequired => false;
+
+        private Carousel OwningCarousel
+        {
+            get
+            {
+                return Owner as Carousel;
+            }
+        }
+
+        /// <summary>Retrieves a UI Automation provider for each child element that is selected.</summary>
+        /// <returns>An array of UI Automation providers.</returns>
+        public IRawElementProviderSimple[] GetSelection()
+        {
+            CarouselItem selectedCarouselItem = OwningCarousel.GetCarouselItems().FirstOrDefault(x => x.IsSelected);
+            return selectedCarouselItem != null
+                ? new[] { this.ProviderFromPeer(FromElement(selectedCarouselItem)) }
+                : new IRawElementProviderSimple[] { };
+        }
+
+        /// <summary>
+        /// Gets the control type for the element that is associated with the UI Automation peer.
+        /// </summary>
+        /// <returns>The control type.</returns>
+        protected override AutomationControlType GetAutomationControlTypeCore()
+        {
+            return AutomationControlType.List;
+        }
+
+        /// <summary>
+        /// Called by GetClassName that gets a human readable name that, in addition to AutomationControlType,
+        /// differentiates the control represented by this AutomationPeer.
+        /// </summary>
+        /// <returns>The string that contains the name.</returns>
+        protected override string GetClassNameCore()
+        {
+            return Owner.GetType().Name;
+        }
+
+        /// <summary>
+        /// Called by GetName.
+        /// </summary>
+        /// <returns>
+        /// Returns the first of these that is not null or empty:
+        /// - Value returned by the base implementation
+        /// - Name of the owning Carousel
+        /// - Carousel class name
+        /// </returns>
+        protected override string GetNameCore()
+        {
+            string name = base.GetNameCore();
+            if (!string.IsNullOrEmpty(name))
+            {
+                return name;
+            }
+
+            if (this.OwningCarousel != null)
+            {
+                name = this.OwningCarousel.Name;
+            }
+
+            if (string.IsNullOrEmpty(name))
+            {
+                name = this.GetClassName();
+            }
+
+            return name;
+        }
+
+        /// <summary>
+        /// Gets the control pattern that is associated with the specified Windows.UI.Xaml.Automation.Peers.PatternInterface.
+        /// </summary>
+        /// <param name="patternInterface">A value from the Windows.UI.Xaml.Automation.Peers.PatternInterface enumeration.</param>
+        /// <returns>The object that supports the specified pattern, or null if unsupported.</returns>
+        protected override object GetPatternCore(PatternInterface patternInterface)
+        {
+            switch (patternInterface)
+            {
+                case PatternInterface.Selection:
+                    return this;
+            }
+
+            return base.GetPatternCore(patternInterface);
+        }
+
+        /// <summary>
+        /// Gets the collection of elements that are represented in the UI Automation tree as immediate
+        /// child elements of the automation peer.
+        /// </summary>
+        /// <returns>The children elements.</returns>
+        protected override IList<AutomationPeer> GetChildrenCore()
+        {
+            Carousel owner = OwningCarousel;
+
+            ItemCollection items = owner.Items;
+            if (items.Count <= 0)
+            {
+                return null;
+            }
+
+            List<AutomationPeer> peers = new List<AutomationPeer>(items.Count);
+            for (int i = 0; i < items.Count; i++)
+            {
+                if (owner.ContainerFromIndex(i) is CarouselItem element)
+                {
+                    peers.Add(FromElement(element) ?? CreatePeerForElement(element));
+                }
+            }
+
+            return peers;
+        }
+    }
+}

Microsoft.Toolkit.Uwp.UI.Controls/Carousel/CarouselItem.cs

@@ -4,6 +4,7 @@
 
 using System;
 using Windows.UI.Xaml;
+using Windows.UI.Xaml.Automation.Peers;
 using Windows.UI.Xaml.Controls;
 using Windows.UI.Xaml.Controls.Primitives;
 using Windows.UI.Xaml.Input;
@@ -33,6 +34,8 @@ public CarouselItem()
             RegisterPropertyChangedCallback(SelectorItem.IsSelectedProperty, OnIsSelectedChanged);
         }
 
+        internal Carousel ParentCarousel { get; set; }
+
         /// <inheritdoc/>
         protected override void OnPointerEntered(PointerRoutedEventArgs e)
         {
@@ -57,6 +60,15 @@ protected override void OnPointerPressed(PointerRoutedEventArgs e)
             VisualStateManager.GoToState(this, IsSelected ? PressedSelectedState : PressedState, true);
         }
 
+        /// <summary>
+        /// Creates AutomationPeer (<see cref="UIElement.OnCreateAutomationPeer"/>)
+        /// </summary>
+        /// <returns>An automation peer for this <see cref="CarouselItem"/>.</returns>
+        protected override AutomationPeer OnCreateAutomationPeer()
+        {
+            return new CarouselItemAutomationPeer(this);
+        }
+
         internal event EventHandler Selected;
 
         private void OnIsSelectedChanged(DependencyObject sender, DependencyProperty dp)

Microsoft.Toolkit.Uwp.UI.Controls/Carousel/CarouselItemAutomationPeer.cs

@@ -0,0 +1,144 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Linq;
+using Windows.UI.Xaml.Automation.Peers;
+using Windows.UI.Xaml.Automation.Provider;
+
+namespace Microsoft.Toolkit.Uwp.UI.Controls
+{
+    /// <summary>
+    /// Defines a framework element automation peer for the <see cref="CarouselItem"/>.
+    /// </summary>
+    public class CarouselItemAutomationPeer : FrameworkElementAutomationPeer, ISelectionItemProvider
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="CarouselItemAutomationPeer"/> class.
+        /// </summary>
+        /// <param name="owner">
+        /// The <see cref="CarouselItem" /> that is associated with this <see cref="T:Windows.UI.Xaml.Automation.Peers.CarouselItemAutomationPeer" />.
+        /// </param>
+        public CarouselItemAutomationPeer(CarouselItem owner)
+            : base(owner)
+        {
+        }
+
+        /// <summary>Gets a value indicating whether an item is selected.</summary>
+        /// <returns>True if the element is selected; otherwise, false.</returns>
+        public bool IsSelected => this.OwnerCarouselItem.IsSelected;
+
+        /// <summary>Gets the UI Automation provider that implements ISelectionProvider and acts as the container for the calling object.</summary>
+        /// <returns>The UI Automation provider.</returns>
+        public IRawElementProviderSimple SelectionContainer
+        {
+            get
+            {
+                Carousel parent = this.OwnerCarouselItem.ParentCarousel;
+                if (parent == null)
+                {
+                    return null;
+                }
+
+                AutomationPeer peer = FromElement(parent);
+                return peer != null ? this.ProviderFromPeer(peer) : null;
+            }
+        }
+
+        private CarouselItem OwnerCarouselItem
+        {
+            get { return this.Owner as CarouselItem; }
+        }
+
+        /// <summary>Adds the current element to the collection of selected items.</summary>
+        public void AddToSelection()
+        {
+            CarouselItem owner = this.OwnerCarouselItem;
+            Carousel parent = owner.ParentCarousel;
+            parent.SetSelectedItem(owner);
+        }
+
+        /// <summary>Removes the current element from the collection of selected items.</summary>
+        public void RemoveFromSelection()
+        {
+            CarouselItem owner = this.OwnerCarouselItem;
+            Carousel parent = owner.ParentCarousel;
+            parent.SelectedItem = null;
+        }
+
+        /// <summary>Clears any existing selection and then selects the current element.</summary>
+        public void Select()
+        {
+            CarouselItem owner = this.OwnerCarouselItem;
+            Carousel parent = owner.ParentCarousel;
+            parent.SetSelectedItem(owner);
+        }
+
+        /// <summary>
+        /// Gets the control type for the element that is associated with the UI Automation peer.
+        /// </summary>
+        /// <returns>The control type.</returns>
+        protected override AutomationControlType GetAutomationControlTypeCore()
+        {
+            return AutomationControlType.ListItem;
+        }
+
+        /// <summary>
+        /// Called by GetClassName that gets a human readable name that, in addition to AutomationControlType,
+        /// differentiates the control represented by this AutomationPeer.
+        /// </summary>
+        /// <returns>The string that contains the name.</returns>
+        protected override string GetClassNameCore()
+        {
+            return Owner.GetType().Name;
+        }
+
+        /// <summary>
+        /// Called by GetName.
+        /// </summary>
+        /// <returns>
+        /// Returns the first of these that is not null or empty:
+        /// - Value returned by the base implementation
+        /// - Name of the owning CarouselItem
+        /// - Carousel class name
+        /// </returns>
+        protected override string GetNameCore()
+        {
+            int? index = this.OwnerCarouselItem.ParentCarousel.GetCarouselItems().ToList().IndexOf(this.OwnerCarouselItem);
+
+            string name = base.GetNameCore();
+            if (!string.IsNullOrEmpty(name))
+            {
+                return $"{name} {index}";
+            }
+
+            if (this.OwnerCarouselItem != null && !string.IsNullOrEmpty(this.OwnerCarouselItem.Name))
+            {
+                return this.OwnerCarouselItem.Name;
+            }
+
+            if (string.IsNullOrEmpty(name))
+            {
+                name = this.GetClassName();
+            }
+
+            return $"{name} {index}";
+        }
+
+        /// <summary>
+        /// Gets the control pattern that is associated with the specified Windows.UI.Xaml.Automation.Peers.PatternInterface.
+        /// </summary>
+        /// <param name="patternInterface">A value from the Windows.UI.Xaml.Automation.Peers.PatternInterface enumeration.</param>
+        /// <returns>The object that supports the specified pattern, or null if unsupported.</returns>
+        protected override object GetPatternCore(PatternInterface patternInterface)
+        {
+            switch (patternInterface)
+            {
+                case PatternInterface.SelectionItem:
+                    return this;
+            }
+
+            return base.GetPatternCore(patternInterface);
+        }
+    }
+}