From 11130370137a7ca0b12087c93f6510209c7af989 Mon Sep 17 00:00:00 2001
From: Kenny Guo <kennyguo@microsoft.com>
Date: Fri, 30 Jul 2021 10:28:37 +0800
Subject: [PATCH] Use automation peer to trigger back button click in
 accelerator

---
 src/Calculator/Views/MainPage.xaml.cs |  2 +-
 src/Calculator/Views/TitleBar.xaml.cs | 18 +++++++-----------
 2 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/src/Calculator/Views/MainPage.xaml.cs b/src/Calculator/Views/MainPage.xaml.cs
index f6cc0aee..1862b197 100644
--- a/src/Calculator/Views/MainPage.xaml.cs
+++ b/src/Calculator/Views/MainPage.xaml.cs
@@ -578,7 +578,7 @@ namespace CalculatorApp
             NarratorNotifier.Announce(announcement);
         }
 
-        private void TitleBarBackButtonClick(object sender)
+        private void TitleBarBackButtonClick(object sender, RoutedEventArgs e)
         {
             CloseSettingsPopup();
         }
diff --git a/src/Calculator/Views/TitleBar.xaml.cs b/src/Calculator/Views/TitleBar.xaml.cs
index e498a878..2797e5bb 100644
--- a/src/Calculator/Views/TitleBar.xaml.cs
+++ b/src/Calculator/Views/TitleBar.xaml.cs
@@ -7,6 +7,8 @@ using Windows.UI;
 using Windows.UI.Core;
 using Windows.UI.ViewManagement;
 using Windows.UI.Xaml;
+using Windows.UI.Xaml.Automation.Peers;
+using Windows.UI.Xaml.Automation.Provider;
 using Windows.UI.Xaml.Controls;
 using Windows.UI.Xaml.Media;
 
@@ -51,9 +53,7 @@ namespace CalculatorApp
             }));
 
         public event Windows.UI.Xaml.RoutedEventHandler AlwaysOnTopClick;
-
-        public delegate void BackButtonClickEventHandler(object sender);
-        public event BackButtonClickEventHandler BackButtonClick;
+        public event Windows.UI.Xaml.RoutedEventHandler BackButtonClick;
 
         private void OnLoaded(object sender, RoutedEventArgs e)
         {
@@ -103,7 +103,9 @@ namespace CalculatorApp
         {
             if (!e.Handled && BackButton.IsEnabled)
             {
-                InvokeBackButton(sender) ;
+                var buttonPeer = new ButtonAutomationPeer(BackButton);
+                IInvokeProvider invokeProvider = buttonPeer.GetPattern(PatternInterface.Invoke) as IInvokeProvider;
+                invokeProvider.Invoke();
 
                 e.Handled = true;
             }
@@ -229,15 +231,9 @@ namespace CalculatorApp
             AlwaysOnTopClick?.Invoke(this, e);
         }
 
-        // Called when BackButton invoked, for example, by clicking, access key and etc.
-        private void InvokeBackButton(object sender)
-        {
-            BackButtonClick?.Invoke(this);
-        }
-
         private void BackButton_Click(object sender, RoutedEventArgs e)
         {
-            InvokeBackButton(sender);
+            BackButtonClick?.Invoke(this, e);
         }
 
         // Dependency properties for the color of the system title bar buttons