Implement ContextMenu interactions.

src/Avalonia.Controls/ContextMenu.cs

@@ -1,16 +1,18 @@
+using System;
+using System.Reactive.Linq;
+using System.Linq;
+using System.ComponentModel;
+using Avalonia.Controls.Platform;
+using System.Collections.Generic;
+using Avalonia.Input;
+using Avalonia.LogicalTree;
+using Avalonia.Controls.Primitives;
+
 namespace Avalonia.Controls
 {
-    using Input;
-    using Interactivity;
-    using LogicalTree;
-    using Primitives;
-    using System;
-    using System.Reactive.Linq;
-    using System.Linq;
-    using System.ComponentModel;
-
-    public class ContextMenu : SelectingItemsControl
+    public class ContextMenu : SelectingItemsControl, IMenu
     {
+        private readonly IMenuInteractionHandler _interaction;
         private bool _isOpen;
         private Popup _popup;
 
@@ -20,6 +22,25 @@ namespace Avalonia.Controls
         public static readonly DirectProperty<ContextMenu, bool> IsOpenProperty =
                             AvaloniaProperty.RegisterDirect<ContextMenu, bool>(nameof(IsOpen), o => o.IsOpen);
 
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ContextMenu"/> class.
+        /// </summary>
+        public ContextMenu()
+        {
+            _interaction = AvaloniaLocator.Current.GetService<IMenuInteractionHandler>() ??
+                new DefaultMenuInteractionHandler();
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ContextMenu"/> class.
+        /// </summary>
+        /// <param name="interactionHandler">The menu iteraction handler.</param>
+        public ContextMenu(IMenuInteractionHandler interactionHandler)
+        {
+            Contract.Requires<ArgumentNullException>(interactionHandler != null);
+
+            _interaction = interactionHandler;
+        }
 
         /// <summary>
         /// Initializes static members of the <see cref="ContextMenu"/> class.
@@ -27,8 +48,6 @@ namespace Avalonia.Controls
         static ContextMenu()
         {
             ContextMenuProperty.Changed.Subscribe(ContextMenuChanged);
-
-            MenuItem.ClickEvent.AddClassHandler<ContextMenu>(x => x.OnContextMenuClick, handledEventsToo: true);
         }
 
         /// <summary>
@@ -36,6 +55,36 @@ namespace Avalonia.Controls
         /// </summary>
         public bool IsOpen => _isOpen;
 
+        /// <inheritdoc/>
+        IMenuInteractionHandler IMenu.InteractionHandler => _interaction;
+
+        /// <inheritdoc/>
+        IMenuItem IMenuElement.SelectedItem
+        {
+            get
+            {
+                var index = SelectedIndex;
+                return (index != -1) ?
+                    (IMenuItem)ItemContainerGenerator.ContainerFromIndex(index) :
+                    null;
+            }
+            set
+            {
+                SelectedIndex = ItemContainerGenerator.IndexFromContainer(value);
+            }
+        }
+
+        /// <inheritdoc/>
+        IEnumerable<IMenuItem> IMenuElement.SubItems
+        {
+            get
+            {
+                return ItemContainerGenerator.Containers
+                    .Select(x => x.ContainerControl)
+                    .OfType<IMenuItem>();
+            }
+        }
+
         /// <summary>
         /// Occurs when the value of the
         /// <see cref="P:Avalonia.Controls.ContextMenu.IsOpen" />
@@ -50,7 +99,6 @@ namespace Avalonia.Controls
         /// </summary>
         public event CancelEventHandler ContextMenuClosing;
 
-
         /// <summary>
         /// Called when the <see cref="Control.ContextMenu"/> property changes on a control.
         /// </summary>
@@ -71,62 +119,53 @@ namespace Avalonia.Controls
         }
 
         /// <summary>
-        /// Called when a submenu is clicked somewhere in the menu.
+        /// Opens the menu.
         /// </summary>
-        /// <param name="e">The event args.</param>
-        private void OnContextMenuClick(RoutedEventArgs e)
-        {
-            Hide();
-            FocusManager.Instance.Focus(null);
-            e.Handled = true;
-        }
+        public void Open() => Open(null);
 
         /// <summary>
-        /// Closes the menu.
+        /// Opens a context menu on the specified control.
         /// </summary>
-        public void Hide()
+        /// <param name="control">The control.</param>
+        public void Open(Control control)
         {
-            if (_popup != null && _popup.IsVisible)
+            if (_popup == null)
             {
-                _popup.IsOpen = false;
+                _popup = new Popup()
+                {
+                    PlacementMode = PlacementMode.Pointer,
+                    PlacementTarget = control,
+                    StaysOpen = false,
+                    ObeyScreenEdges = true
+                };
+
+                _popup.Closed += PopupClosed;
+                _interaction.Attach(this);
             }
 
-            SelectedIndex = -1;
+            ((ISetLogicalParent)_popup).SetParent(control);
+            _popup.Child = this;
+            _popup.IsOpen = true;
 
-            SetAndRaise(IsOpenProperty, ref _isOpen, false);
+            SetAndRaise(IsOpenProperty, ref _isOpen, true);
         }
 
         /// <summary>
-        /// Shows a context menu for the specified control.
+        /// Closes the menu.
         /// </summary>
-        /// <param name="control">The control.</param>
-        private void Show(Control control)
+        public void Close()
         {
-            if (control != null)
+            if (_popup != null && _popup.IsVisible)
             {
-                if (_popup == null)
-                {
-                    _popup = new Popup()
-                    {
-                        PlacementMode = PlacementMode.Pointer,
-                        PlacementTarget = control,
-                        StaysOpen = false,
-                        ObeyScreenEdges = true
-                    };
-
-                    _popup.Closed += PopupClosed;
-                }
-
-                ((ISetLogicalParent)_popup).SetParent(control);
-                _popup.Child = this;
+                _popup.IsOpen = false;
+            }
 
-                _popup.IsOpen = true;
+            SelectedIndex = -1;
 
-                SetAndRaise(IsOpenProperty, ref _isOpen, true);
-            }
+            SetAndRaise(IsOpenProperty, ref _isOpen, false);
         }
 
-        private static void PopupClosed(object sender, EventArgs e)
+        private void PopupClosed(object sender, EventArgs e)
         {
             var contextMenu = (sender as Popup)?.Child as ContextMenu;
 
@@ -152,7 +191,7 @@ namespace Avalonia.Controls
                 if (contextMenu.CancelClosing())
                     return;
 
-                control.ContextMenu.Hide();
+                control.ContextMenu.Close();
                 e.Handled = true;
             }
 
@@ -161,7 +200,7 @@ namespace Avalonia.Controls
                 if (contextMenu.CancelOpening())
                     return;
 
-                contextMenu.Show(control);
+                contextMenu.Open(control);
                 e.Handled = true;
             }
         }
@@ -179,5 +218,10 @@ namespace Avalonia.Controls
             ContextMenuOpening?.Invoke(this, eventArgs);
             return eventArgs.Cancel;
         }
+
+        bool IMenuElement.MoveSelection(NavigationDirection direction, bool wrap)
+        {
+            throw new NotImplementedException();
+        }
     }
 }