Add TabView SelectionPattern

dev/TabView/APITests/TabViewTests.cs

@@ -10,6 +10,9 @@
 using Common;
 using Microsoft.UI.Xaml.Controls;
 using System.Collections.Generic;
+using Windows.UI.Xaml.Automation.Peers;
+using Windows.UI.Xaml.Automation;
+using Windows.UI.Xaml.Automation.Provider;
 
 #if USING_TAEF
 using WEX.TestExecution;
@@ -84,6 +87,31 @@ public void VerifyCompactTabWidthVisualStates()
             });
         }
 
+        [TestMethod]
+        public void VerifyUIABehavior()
+        {
+            RunOnUIThread.Execute(() =>
+            {
+                TabView tabView = new TabView();
+                Content = tabView;
+
+                tabView.TabItems.Add(CreateTabViewItem("Item 0", Symbol.Add));
+                tabView.TabItems.Add(CreateTabViewItem("Item 1", Symbol.AddFriend));
+                tabView.TabItems.Add(CreateTabViewItem("Item 2"));
+
+                Content.UpdateLayout();
+
+                var tabViewPeer = FrameworkElementAutomationPeer.CreatePeerForElement(tabView);
+                Verify.IsNotNull(tabViewPeer);
+                var tabViewSelectionPattern = tabViewPeer.GetPattern(PatternInterface.Selection);
+                Verify.IsNotNull(tabViewSelectionPattern);
+                var selectionProvider = tabViewSelectionPattern as ISelectionProvider;
+                // Tab controls must require selection
+                Verify.IsTrue(selectionProvider.IsSelectionRequired);
+            });
+        }
+
+
         private static void VerifyTabWidthVisualStates(IList<object> items, bool isCompact)
         {
             foreach (var item in items)

dev/TabView/TabViewAutomationPeer.cpp

@@ -18,6 +18,10 @@ TabViewAutomationPeer::TabViewAutomationPeer(winrt::TabView const& owner)
 // IAutomationPeerOverrides
 winrt::IInspectable TabViewAutomationPeer::GetPatternCore(winrt::PatternInterface const& patternInterface)
 {
+    if (patternInterface == winrt::PatternInterface::Selection)
+    {
+        return *this;
+    }
     return __super::GetPatternCore(patternInterface);
 }
 
@@ -31,3 +35,27 @@ winrt::AutomationControlType TabViewAutomationPeer::GetAutomationControlTypeCore
     return winrt::AutomationControlType::Tab;
 }
 
+bool TabViewAutomationPeer::CanSelectMultiple()
+{
+    return false;
+}
+
+bool TabViewAutomationPeer::IsSelectionRequired()
+{
+    return true;
+}
+
+winrt::com_array<winrt::Windows::UI::Xaml::Automation::Provider::IRawElementProviderSimple> TabViewAutomationPeer::GetSelection()
+{
+    if (auto tabView = Owner().try_as<TabView>())
+    {
+        if (auto tabViewItem = tabView->ContainerFromIndex(tabView->SelectedIndex()).try_as<winrt::TabViewItem>())
+        {
+            if (auto peer = winrt::FrameworkElementAutomationPeer::CreatePeerForElement(tabViewItem))
+            {
+                return { ProviderFromPeer(peer) };
+            }
+        }
+    }
+    return {};
+}

dev/TabView/TabViewAutomationPeer.h

@@ -7,7 +7,9 @@
 #include "TabViewAutomationPeer.g.h"
 
 class TabViewAutomationPeer :
-    public ReferenceTracker<TabViewAutomationPeer, winrt::implementation::TabViewAutomationPeerT>
+    public ReferenceTracker<TabViewAutomationPeer,
+    winrt::implementation::TabViewAutomationPeerT,
+    winrt::ISelectionProvider>
 {
 
 public:
@@ -17,4 +19,9 @@ class TabViewAutomationPeer :
     winrt::IInspectable GetPatternCore(winrt::PatternInterface const& patternInterface);
     hstring GetClassNameCore();
     winrt::AutomationControlType GetAutomationControlTypeCore();
+
+    // ISelectionProvider
+    bool CanSelectMultiple();
+    bool IsSelectionRequired();
+    winrt::com_array<winrt::Windows::UI::Xaml::Automation::Provider::IRawElementProviderSimple> GetSelection();
 };