From b116d94c3a058e278800e44ee50d1edfb9663ee0 Mon Sep 17 00:00:00 2001
From: Steven Kirk <steven.kirk@tricycleinc.com>
Date: Sun, 5 Apr 2015 18:02:29 -0400
Subject: [PATCH] Added Button.IsDefault

---
 Perspex.Controls/Button.cs            | 79 +++++++++++++++++++++++++++
 Perspex.Interactivity/IInteractive.cs | 19 +++++++
 TestApplication/Program.cs            | 11 ++++
 3 files changed, 109 insertions(+)

diff --git a/Perspex.Controls/Button.cs b/Perspex.Controls/Button.cs
index 197194389c..4c418a347e 100644
--- a/Perspex.Controls/Button.cs
+++ b/Perspex.Controls/Button.cs
@@ -7,9 +7,12 @@
 namespace Perspex.Controls
 {
     using System;
+    using System.Linq;
     using System.Windows.Input;
     using Perspex.Input;
     using Perspex.Interactivity;
+    using Perspex.Rendering;
+    using Perspex.VisualTree;
 
     public enum ClickMode
     {
@@ -28,6 +31,9 @@ namespace Perspex.Controls
         public static readonly PerspexProperty<object> CommandParameterProperty =
             PerspexProperty.Register<Button, object>("CommandParameter");
 
+        public static readonly PerspexProperty<bool> IsDefaultProperty =
+            PerspexProperty.Register<Button, bool>("IsDefault");
+
         public static readonly RoutedEvent<RoutedEventArgs> ClickEvent =
             RoutedEvent.Register<Button, RoutedEventArgs>("Click", RoutingStrategies.Bubble);
 
@@ -36,6 +42,7 @@ namespace Perspex.Controls
             FocusableProperty.OverrideDefaultValue(typeof(Button), true);
             ClickEvent.AddClassHandler<Button>(x => x.OnClick);
             CommandProperty.Changed.Subscribe(CommandChanged);
+            IsDefaultProperty.Changed.Subscribe(IsDefaultChanged);
         }
 
         public event EventHandler<RoutedEventArgs> Click
@@ -62,6 +69,12 @@ namespace Perspex.Controls
             set { this.SetValue(CommandParameterProperty, value); }
         }
 
+        public bool IsDefault
+        {
+            get { return this.GetValue(IsDefaultProperty); }
+            set { this.SetValue(IsDefaultProperty, value); }
+        }
+
         protected override Size MeasureOverride(Size availableSize)
         {
             return base.MeasureOverride(availableSize);
@@ -72,6 +85,34 @@ namespace Perspex.Controls
             return base.ArrangeOverride(finalSize);
         }
 
+        protected override void OnAttachedToVisualTree(IRenderRoot root)
+        {
+            base.OnAttachedToVisualTree(root);
+
+            if (this.IsDefault)
+            {
+                var inputElement = root as IInputElement;
+
+                if (inputElement != null)
+                {
+                    this.ListenForDefault(inputElement);
+                }
+            }
+        }
+
+        protected override void OnDetachedFromVisualTree(IRenderRoot oldRoot)
+        {
+            if (this.IsDefault)
+            {
+                var inputElement = oldRoot as IInputElement;
+
+                if (inputElement != null)
+                {
+                    this.StopListeningForDefault(inputElement);
+                }
+            }
+        }
+
         protected virtual void OnClick(RoutedEventArgs e)
         {
             if (this.Command != null)
@@ -131,6 +172,26 @@ namespace Perspex.Controls
             }
         }
 
+        private static void IsDefaultChanged(PerspexPropertyChangedEventArgs e)
+        {
+            var button = e.Sender as Button;
+            var isDefault = (bool)e.NewValue;
+            var root = button.GetSelfAndVisualAncestors().OfType<IRenderRoot>().FirstOrDefault();
+            var inputElement = root as IInputElement;
+
+            if (inputElement != null)
+            {
+                if (isDefault)
+                {
+                    button.ListenForDefault(inputElement);
+                }
+                else
+                {
+                    button.StopListeningForDefault(inputElement);
+                }
+            }
+        }
+
         private void CanExecuteChanged(object sender, EventArgs e)
         {
             // HACK: Just set the IsEnabled property for the moment. This needs to be changed to 
@@ -138,6 +199,16 @@ namespace Perspex.Controls
             this.IsEnabled = this.Command == null || this.Command.CanExecute(this.CommandParameter);
         }
 
+        private void ListenForDefault(IInputElement root)
+        {
+            root.AddHandler(InputElement.KeyDownEvent, this.RootKeyDown, RoutingStrategies.Tunnel);
+        }
+
+        private void StopListeningForDefault(IInputElement root)
+        {
+            root.RemoveHandler(InputElement.KeyDownEvent, this.RootKeyDown);
+        }
+
         private void RaiseClickEvent()
         {
             RoutedEventArgs click = new RoutedEventArgs
@@ -147,5 +218,13 @@ namespace Perspex.Controls
 
             this.RaiseEvent(click);
         }
+
+        private void RootKeyDown(object sender, KeyEventArgs e)
+        {
+            if (e.Key == Key.Enter && this.IsVisible && this.IsEnabled)
+            {
+                this.RaiseClickEvent();
+            }
+        }
     }
 }
diff --git a/Perspex.Interactivity/IInteractive.cs b/Perspex.Interactivity/IInteractive.cs
index d1b2d7a8b3..b18146d2ec 100644
--- a/Perspex.Interactivity/IInteractive.cs
+++ b/Perspex.Interactivity/IInteractive.cs
@@ -6,8 +6,27 @@
 
 namespace Perspex.Interactivity
 {
+    using System;
+
     public interface IInteractive : IVisual
     {
+        IDisposable AddHandler(
+            RoutedEvent routedEvent,
+            Delegate handler,
+            RoutingStrategies routes = RoutingStrategies.Direct | RoutingStrategies.Bubble,
+            bool handledEventsToo = false);
+
+        IDisposable AddHandler<TEventArgs>(
+            RoutedEvent<TEventArgs> routedEvent,
+            EventHandler<TEventArgs> handler,
+            RoutingStrategies routes = RoutingStrategies.Direct | RoutingStrategies.Bubble,
+            bool handledEventsToo = false) where TEventArgs : RoutedEventArgs;
+
+        void RemoveHandler(RoutedEvent routedEvent, Delegate handler);
+
+        void RemoveHandler<TEventArgs>(RoutedEvent<TEventArgs> routedEvent, EventHandler<TEventArgs> handler)
+            where TEventArgs : RoutedEventArgs;
+
         void RaiseEvent(RoutedEventArgs e);
     }
 }
diff --git a/TestApplication/Program.cs b/TestApplication/Program.cs
index 4e9a2441ad..333e5b65d0 100644
--- a/TestApplication/Program.cs
+++ b/TestApplication/Program.cs
@@ -188,6 +188,7 @@ namespace TestApplication
 
         private static TabItem ButtonsTab()
         {
+            Button defaultButton;
             var showDialog = ReactiveCommand.Create();
             Button showDialogButton;
             
@@ -213,6 +214,11 @@ namespace TestApplication
                             Content = "Button",
                             Background = new SolidColorBrush(0xcc119eda),
                         },
+                        (defaultButton = new Button
+                        {
+                            Content = "Default",
+                            IsDefault = true,
+                        }),
                         new Button
                         {
                             Content = "Disabled",
@@ -250,6 +256,11 @@ namespace TestApplication
                 },
             };
 
+            defaultButton.Click += (s, e) =>
+            {
+                defaultButton.Content = ((string)defaultButton.Content == "Default") ? "Clicked" : "Default";
+            };
+
             showDialog.Subscribe(async _ =>
             {
                 var close = ReactiveCommand.Create();