From 26109a2828e77357ba155d81cf4720336768d4f2 Mon Sep 17 00:00:00 2001
From: Marcel Wagner <marcel.alex.wagner@outlook.com>
Date: Sat, 27 Jun 2020 20:05:50 +0200
Subject: [PATCH 1/2] Fix issue with collapse being announced on NavViewItem
 with no children

---
 dev/NavigationView/NavigationViewItem.h            |  2 +-
 .../NavigationViewItemAutomationPeer.cpp           | 14 ++++++++++++--
 .../NavigationViewItemAutomationPeer.h             |  1 +
 3 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/dev/NavigationView/NavigationViewItem.h b/dev/NavigationView/NavigationViewItem.h
index 99978e0117..cff70cbcd0 100644
--- a/dev/NavigationView/NavigationViewItem.h
+++ b/dev/NavigationView/NavigationViewItem.h
@@ -58,6 +58,7 @@ class NavigationViewItem :
     void RotateExpandCollapseChevron(bool isExpanded);
     bool IsRepeaterVisible() const;
     void PropagateDepthToChildren(int depth);
+    bool HasChildren();
 
 private:
     winrt::UIElement const GetPresenterOrItem() const;
@@ -97,7 +98,6 @@ class NavigationViewItem :
     bool ShouldEnableToolTip() const;
     bool IsOnLeftNav() const;
     bool IsOnTopPrimary() const;
-    bool HasChildren();
 
     void UpdateRepeaterItemsSource();
     void ReparentRepeater();
diff --git a/dev/NavigationView/NavigationViewItemAutomationPeer.cpp b/dev/NavigationView/NavigationViewItemAutomationPeer.cpp
index fb2add6650..fdcc74465e 100644
--- a/dev/NavigationView/NavigationViewItemAutomationPeer.cpp
+++ b/dev/NavigationView/NavigationViewItemAutomationPeer.cpp
@@ -1,4 +1,4 @@
-// Copyright (c) Microsoft Corporation. All rights reserved.
+// Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License. See LICENSE in the project root for license information.
 
 #include "pch.h"
@@ -48,7 +48,8 @@ winrt::IInspectable NavigationViewItemAutomationPeer::GetPatternCore(winrt::Patt
 {
     if (pattern == winrt::PatternInterface::SelectionItem ||
         pattern == winrt::PatternInterface::Invoke ||
-        pattern == winrt::PatternInterface::ExpandCollapse)
+        // Only provide expand collapse pattern if we have children!
+        (pattern == winrt::PatternInterface::ExpandCollapse && HasChildren()))
     {
         return *this;
     }
@@ -457,3 +458,12 @@ void NavigationViewItemAutomationPeer::ChangeSelection(bool isSelected)
         nvi.IsSelected(isSelected);
     }
 }
+
+bool NavigationViewItemAutomationPeer::HasChildren()
+{
+    if (const auto& navigationViewItem = Owner().try_as<NavigationViewItem>())
+    {
+        return navigationViewItem->HasChildren();
+    }
+    return false;
+}
diff --git a/dev/NavigationView/NavigationViewItemAutomationPeer.h b/dev/NavigationView/NavigationViewItemAutomationPeer.h
index 387e6e48ed..f84a8a9ba0 100644
--- a/dev/NavigationView/NavigationViewItemAutomationPeer.h
+++ b/dev/NavigationView/NavigationViewItemAutomationPeer.h
@@ -62,4 +62,5 @@ class NavigationViewItemAutomationPeer :
     int32_t GetPositionOrSetCountInLeftNavHelper(AutomationOutput automationOutput);
     int32_t GetPositionOrSetCountInTopNavHelper(AutomationOutput automationOutput);
     void ChangeSelection(bool isSelected);
+    bool HasChildren();
 };

From 71e0f6bcfd65369b538ec4fdcb1c9b7529ca4b22 Mon Sep 17 00:00:00 2001
From: Marcel Wagner <marcel.alex.wagner@outlook.com>
Date: Sat, 27 Jun 2020 20:05:56 +0200
Subject: [PATCH 2/2] Add test

---
 .../NavigationViewTests.cs                    | 31 +++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/dev/NavigationView/NavigationView_ApiTests/NavigationViewTests.cs b/dev/NavigationView/NavigationView_ApiTests/NavigationViewTests.cs
index a3f1c295c5..43ad0c5244 100644
--- a/dev/NavigationView/NavigationView_ApiTests/NavigationViewTests.cs
+++ b/dev/NavigationView/NavigationView_ApiTests/NavigationViewTests.cs
@@ -535,6 +535,37 @@ 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()
         {