[FZ Editor] Custom button with automation event on click (#12338)

* Custom button with automation event on click

* Rename MyButton to ClickAutomationEventButton

* Rename property to OnClickAutomationValue

* Remove unneeded line

src/modules/fancyzones/editor/FancyZonesEditor/ClickAutomationEventButton.xaml.cs

@@ -0,0 +1,105 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Windows;
+using System.Windows.Automation;
+using System.Windows.Automation.Peers;
+using System.Windows.Automation.Provider;
+using System.Windows.Controls;
+
+namespace FancyZonesEditor
+{
+    public partial class ClickAutomationEventButton : Button
+    {
+        public ClickAutomationEventButton()
+            : base()
+        {
+            InitializeComponent();
+            Click += OnClick;
+        }
+
+        public string OnClickAutomationValue
+        {
+            get { return (string)GetValue(OnClickAutomationValueProperty); }
+            set { SetValue(OnClickAutomationValueProperty, value); }
+        }
+
+        public static readonly DependencyProperty OnClickAutomationValueProperty =
+        DependencyProperty.Register(
+            "Value", typeof(string), typeof(ClickAutomationEventButton));
+
+        private void OnClick(object sender, RoutedEventArgs e)
+        {
+            if (AutomationPeer.ListenerExists(AutomationEvents.PropertyChanged))
+            {
+                ClickAutomationEventButtonAutomationPeer peer =
+                    UIElementAutomationPeer.FromElement(this) as ClickAutomationEventButtonAutomationPeer;
+
+                if (peer != null)
+                {
+                    peer.RaisePropertyChangedEvent(
+                        ValuePatternIdentifiers.ValueProperty,
+                        null,
+                        OnClickAutomationValue);
+                }
+            }
+        }
+
+        protected override AutomationPeer OnCreateAutomationPeer()
+        {
+            return new ClickAutomationEventButtonAutomationPeer(this);
+        }
+
+        public class ClickAutomationEventButtonAutomationPeer : FrameworkElementAutomationPeer, IValueProvider
+        {
+            public ClickAutomationEventButtonAutomationPeer(ClickAutomationEventButton control)
+                : base(control)
+            {
+            }
+
+            protected override string GetClassNameCore()
+            {
+                return nameof(ClickAutomationEventButton);
+            }
+
+            protected override AutomationControlType GetAutomationControlTypeCore()
+            {
+                return AutomationControlType.Button;
+            }
+
+            public override object GetPattern(PatternInterface patternInterface)
+            {
+                if (patternInterface == PatternInterface.Value)
+                {
+                    return this;
+                }
+
+                return base.GetPattern(patternInterface);
+            }
+
+            public void SetValue(string value)
+            {
+                MyOwner.OnClickAutomationValue = value;
+            }
+
+            private ClickAutomationEventButton MyOwner
+            {
+                get
+                {
+                    return (ClickAutomationEventButton)Owner;
+                }
+            }
+
+            public string Value
+            {
+                get { return MyOwner.OnClickAutomationValue; }
+            }
+
+            public bool IsReadOnly
+            {
+                get { return !IsEnabled(); }
+            }
+        }
+    }
+}