Fix issue with NavigationViewItem announcing collapsed when not havin…

…g children (microsoft/microsoft-ui-xaml#2770)
Kinnara · Jul 3, 2020 · a837a1b · a837a1b
1 parent 58198de
commit a837a1b
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Showing 3 changed files with 43 additions and 2 deletions.
diff --git a/ModernWpf.Controls/NavigationView/NavigationViewItem.cs b/ModernWpf.Controls/NavigationView/NavigationViewItem.cs
@@ -491,7 +491,7 @@ void UpdateVisualStateForChevron()
             }
         }
 
-        bool HasChildren()
+        internal bool HasChildren()
         {
             return MenuItems.Count > 0 || MenuItemsSource != null || HasUnrealizedChildren;
         }

diff --git a/ModernWpf.Controls/NavigationView/NavigationViewItemAutomationPeer.cs b/ModernWpf.Controls/NavigationView/NavigationViewItemAutomationPeer.cs
@@ -49,7 +49,8 @@ public override object GetPattern(PatternInterface pattern)
         {
             if (pattern == PatternInterface.SelectionItem ||
                 pattern == PatternInterface.Invoke ||
-                pattern == PatternInterface.ExpandCollapse)
+                // Only provide expand collapse pattern if we have children!
+                (pattern == PatternInterface.ExpandCollapse && HasChildren()))
             {
                 return this;
             }
@@ -443,6 +444,15 @@ void ChangeSelection(bool isSelected)
             }
         }
 
+        bool HasChildren()
+        {
+            if (Owner is NavigationViewItem navigationViewItem)
+            {
+                return navigationViewItem.HasChildren();
+            }
+            return false;
+        }
+
         enum AutomationOutput
         {
             Position,

diff --git a/test/ModernWpfTestApp/ApiTests/NavigationViewTests.cs b/test/ModernWpfTestApp/ApiTests/NavigationViewTests.cs
@@ -540,6 +540,37 @@ public void VerifyNavigationItemUIAType()
             });
         }
 
+        [TestMethod]
+        public void VerifyAutomationPeerExpandCollapsePatternBehavior()
+        {
+            RunOnUIThread.Execute(() =>
+            {
+
+                var menuItem1 = new NavigationViewItem();
+                var menuItem2 = new NavigationViewItem();
+                var menuItem3 = new NavigationViewItem();
+                var menuItem4 = new NavigationViewItem();
+                menuItem1.Content = "Item 1";
+                menuItem2.Content = "Item 2";
+                menuItem3.Content = "Item 3";
+                menuItem4.Content = "Item 4";
+
+                menuItem2.MenuItems.Add(menuItem3);
+                menuItem4.HasUnrealizedChildren = true;
+
+                var expandPeer = NavigationViewItemAutomationPeer.CreatePeerForElement(menuItem1).GetPattern(PatternInterface.ExpandCollapse);
+
+                Verify.IsNull(expandPeer,"Verify NavigationViewItem with no children has no ExpandCollapse pattern");
+
+                expandPeer = NavigationViewItemAutomationPeer.CreatePeerForElement(menuItem2).GetPattern(PatternInterface.ExpandCollapse);
+                Verify.IsNotNull(expandPeer,"Verify NavigationViewItem with children has an ExpandCollapse pattern provided");
+
+                expandPeer = NavigationViewItemAutomationPeer.CreatePeerForElement(menuItem4).GetPattern(PatternInterface.ExpandCollapse);
+                Verify.IsNotNull(expandPeer,"Verify NavigationViewItem without children but with UnrealizedChildren set to true has an ExpandCollapse pattern provided");
+            });
+        }
+
+
         [TestMethod]
         public void VerifySettingsItemToolTip()
         {