TabView.ItemChanged Event Fix

dev/TabView/InteractionTests/TabViewTests.cs

@@ -327,13 +327,6 @@ public void HandleItemCloseRequestedTest()
         [TestMethod]
         public void DragBetweenTabViewsTest()
         {
-            if (PlatformConfiguration.IsOSVersionLessThan(OSVersion.Redstone5))
-            {
-                // TODO 19727004: Re-enable this on versions below RS5 after fixing the bug where mouse click-and-drag doesn't work.
-                Log.Warning("This test relies on touch input, the injection of which is only supported in RS5 and up. Test is disabled.");
-                return;
-            }
-
             using (var setup = new TestSetupHelper("TabView Tests"))
             {
                 UIObject firstTab = FindElement.ByName("FirstTab");
@@ -361,13 +354,6 @@ public void DragBetweenTabViewsTest()
         [TestMethod]
         public void ReorderItemsTest()
         {
-            if (PlatformConfiguration.IsOSVersionLessThan(OSVersion.Redstone5))
-            {
-                // TODO 19727004: Re-enable this on versions below RS5 after fixing the bug where mouse click-and-drag doesn't work.
-                Log.Warning("This test relies on touch input, the injection of which is only supported in RS5 and up. Test is disabled.");
-                return;
-            }
-
             using (var setup = new TestSetupHelper("TabView Tests"))
             {
                 Button tabItemsSourcePageButton = FindElement.ByName<Button>("TabViewTabItemsSourcePageButton");
@@ -405,6 +391,41 @@ public void ReorderItemsTest()
             }
         }
 
+        [TestMethod]
+        public void ItemChangedEventOnDragTest()
+        {
+            using (var setup = new TestSetupHelper("TabView Tests"))
+            {
+                Button addButton = FindElement.ByName<Button>("Add New Tab");
+                Verify.IsNotNull(addButton);
+
+                Log.Comment("Add tab so scroll buttons appear.");
+                addButton.InvokeAndWait();
+
+                Verify.IsTrue(AreScrollButtonsVisible(), "Scroll buttons should appear");
+
+                UIObject sourceTab =  FindElement.ByName("FirstTab");
+
+                Verify.IsNotNull(sourceTab);
+
+                UIObject dropTab = FindElement.ByName("LastTab");
+                Verify.IsNotNull(dropTab);
+
+                Log.Comment("Dragging tab to the last overflow tab...");
+                InputHelper.DragToTarget(sourceTab, dropTab, 40);
+                Wait.ForIdle();
+                ElementCache.Refresh();
+
+                Log.Comment("...reordering done. Expecting a TabView.TabItemsChanged event to be raised with CollectionChange=ItemInserted and Index=5.");
+
+                TextBlock tabsItemChangedEventArgsTextBlock = FindElement.ByName<TextBlock>("TabsItemChangedEventArgsTextBlock");
+                Verify.AreEqual("ItemInserted", tabsItemChangedEventArgsTextBlock.DocumentText);
+
+                TextBlock tabsItemChangedEventArgsIndexTextBlock = FindElement.ByName<TextBlock>("TabsItemChangedEventArgsIndexTextBlock");
+                Verify.AreEqual("5", tabsItemChangedEventArgsIndexTextBlock.DocumentText);
+            }
+        }
+
         [TestMethod]
         public void AddButtonTest()
         {

dev/TabView/TabView.cpp

@@ -720,11 +720,6 @@ void TabView::BringSelectedTabIntoView()
 
 void TabView::OnItemsChanged(winrt::IInspectable const& item)
 {
-    if (m_isDragging)
-    {
-        return;
-    }
-
     if (auto args = item.as<winrt::IVectorChangedEventArgs>())
     {
         m_tabItemsChangedEventSource(*this, args);
@@ -863,11 +858,13 @@ void TabView::OnListViewDragItemsCompleted(const winrt::IInspectable& sender, co
 {
     m_isDragging = false;
 
-    // Selection change was disabled during drag, update SelectedIndex now
+    // Selection may have changed during drag if dragged outside, so we update SelectedIndex again.
     if (auto&& listView = m_listView.get())
     {
         SelectedIndex(listView.SelectedIndex());
         SelectedItem(listView.SelectedItem());
+
+        BringSelectedTabIntoView();
     }
 
     auto item = args.Items().GetAt(0);

dev/TabView/TestUI/TabViewPage.xaml

@@ -119,6 +119,11 @@
                         <Button x:Name="GetScrollIncreaseButtonToolTipButton" AutomationProperties.Name="GetScrollIncreaseButtonToolTipButton" Content="TooltipScrollIncreaseButton" Click="GetScrollIncreaseButtonToolTipButton_Click"/>
                         <TextBlock x:Name="ScrollIncreaseButtonToolTipTextBlock" AutomationProperties.Name="ScrollIncreaseButtonToolTipTextBlock" Margin="4,0,0,0" Text=""/>
                     </StackPanel>
+
+                    <StackPanel Orientation="Horizontal" Margin="0,0,0,8">
+                        <TextBlock x:Name="TabsItemChangedEventArgsTextBlock" AutomationProperties.Name="TabsItemChangedEventArgsTextBlock" Margin="4,0,0,0" Text="" />
+                    <TextBlock x:Name="TabsItemChangedEventArgsIndexTextBlock" AutomationProperties.Name="TabsItemChangedEventArgsIndexTextBlock" Margin="4,0,0,0" Text="" />
+                    </StackPanel>
                 </StackPanel>
             </ScrollViewer>
 

dev/TabView/TestUI/TabViewPage.xaml.cs

@@ -47,6 +47,8 @@ public TabViewPage()
             _iconSource = new SymbolIconSource();
             _iconSource.Symbol = Symbol.Placeholder;
 
+            Tabs.TabItemsChanged += Tabs_TabItemsChanged;
+
             ObservableCollection<TabDataItem> itemSource = new ObservableCollection<TabDataItem>();
             for (int i = 0; i < 5; i++)
             {
@@ -63,6 +65,12 @@ public TabViewPage()
             CacheFirstTabSelectedBackgroundPathFill();
         }
 
+        private void Tabs_TabItemsChanged(TabView sender, Windows.Foundation.Collections.IVectorChangedEventArgs args)
+        {
+            TabsItemChangedEventArgsTextBlock.Text = args.CollectionChange.ToString();
+            TabsItemChangedEventArgsIndexTextBlock.Text = args.Index.ToString();
+        }
+
         private Brush backgroundColorCache;
         private Brush activeTabSelectedBackgroundPathBrushCache;
         private Brush activeTabContentBackgroundBrushCache;