Added FocusManager.

Perspex/Application.cs

@@ -17,6 +17,7 @@ namespace Perspex
         public Application()
         {
             Current = this;
+            this.FocusManager = new FocusManager();
             this.InputManager = new InputManager();
         }
 
@@ -26,6 +27,12 @@ namespace Perspex
             private set;
         }
 
+        public IFocusManager FocusManager
+        {
+            get;
+            private set;
+        }
+
         public InputManager InputManager
         {
             get;
@@ -53,6 +60,7 @@ namespace Perspex
         public void RegisterServices()
         {
             Styler styler = new Styler();
+            Locator.CurrentMutable.Register(() => this.FocusManager, typeof(IFocusManager));
             Locator.CurrentMutable.Register(() => this.InputManager, typeof(IInputManager));
             Locator.CurrentMutable.Register(() => styler, typeof(IStyler));
         }

Perspex/Controls/Button.cs

@@ -13,6 +13,11 @@ namespace Perspex.Controls
         public static readonly RoutedEvent<RoutedEventArgs> ClickEvent =
             RoutedEvent.Register<Button, RoutedEventArgs>("Click", RoutingStrategy.Bubble);
 
+        static Button()
+        {
+            FocusableProperty.OverrideDefaultValue(typeof(Button), true);
+        }
+
         public Button()
         {
             this.PointerPressed += (s, e) =>

Perspex/Controls/Control.cs

@@ -246,7 +246,7 @@ namespace Perspex.Controls
         public bool IsFocused
         {
             get { return this.GetValue(IsFocusedProperty); }
-            set { this.SetValue(IsFocusedProperty, value); }
+            internal set { this.SetValue(IsFocusedProperty, value); }
         }
 
         public string Id
@@ -356,6 +356,12 @@ namespace Perspex.Controls
             set { this.SetValue(WidthProperty, value); }
         }
 
+        bool IFocusable.IsFocused
+        {
+            get { return this.GetValue(IsFocusedProperty); }
+            set { this.SetValue(IsFocusedProperty, value); }
+        }
+
         ILogical ILogical.LogicalParent
         {
             get { return this.Parent; }
@@ -385,7 +391,7 @@ namespace Perspex.Controls
 
         public void Focus()
         {
-            this.IsFocused = true;
+            Locator.Current.GetService<IFocusManager>().Focus(this);
         }
 
         public void InvalidateArrange()

Perspex/Controls/TextBox.cs

@@ -19,10 +19,14 @@ namespace Perspex.Controls
 
         private TextBoxView textBoxView;
 
+        static TextBox()
+        {
+            FocusableProperty.OverrideDefaultValue(typeof(TextBox), true);
+        }
+
         public TextBox()
         {
             this.GetObservable(TextProperty).Subscribe(_ => this.InvalidateVisual());
-            FocusableProperty.OverrideDefaultValue(typeof(TextBox), true);
         }
 
         public int CaretIndex

Perspex/Input/FocusManager.cs

@@ -0,0 +1,31 @@
+// -----------------------------------------------------------------------
+// <copyright file="IFocusManager.cs" company="Steven Kirk">
+// Copyright 2014 MIT Licence. See licence.md for more information.
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace Perspex.Input
+{
+    public class FocusManager : IFocusManager
+    {
+        public IFocusable Current
+        {
+            get;
+            private set;
+        }
+
+        public void Focus(IFocusable control)
+        {
+            if (this.Current != null)
+            {
+                this.Current.IsFocused = false;
+            }
+
+            if (control != null)
+            {
+                control.IsFocused = true;
+                this.Current = control;
+            }
+        }
+    }
+}

Perspex/Input/IFocusManager.cs

@@ -0,0 +1,21 @@
+// -----------------------------------------------------------------------
+// <copyright file="IFocusManager.cs" company="Steven Kirk">
+// Copyright 2014 MIT Licence. See licence.md for more information.
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace Perspex.Input
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Linq;
+    using System.Text;
+    using System.Threading.Tasks;
+
+    public interface IFocusManager
+    {
+        IFocusable Current { get; }
+
+        void Focus(IFocusable focusable);
+    }
+}

Perspex/Input/IFocusable.cs

@@ -10,7 +10,7 @@ namespace Perspex.Input
     {
         bool Focusable { get; }
 
-        bool IsFocused { get; }
+        bool IsFocused { get; set; }
 
         void Focus();
     }

Perspex/Input/InputManager.cs

@@ -69,7 +69,9 @@ namespace Perspex.Input
                 Interactive interactive = device.Captured ?? (hit as Interactive) ?? hit.GetVisualAncestor<Interactive>();
                 IFocusable focusable =
                     device.Captured as IFocusable ??
-                    hit.GetVisualAncestorsAndSelf().OfType<IFocusable>().FirstOrDefault(x => x.Focusable);
+                    hit.GetVisualAncestorsAndSelf()
+                       .OfType<IFocusable>()
+                       .FirstOrDefault(x => x.Focusable);
 
                 if (interactive != null)
                 {

Perspex/Perspex.csproj

@@ -84,6 +84,8 @@
     <Compile Include="Controls\LogicalChildren.cs" />
     <Compile Include="Controls\Panel.cs" />
     <Compile Include="Controls\StackPanel.cs" />
+    <Compile Include="Input\IFocusManager.cs" />
+    <Compile Include="Input\FocusManager.cs" />
     <Compile Include="Input\IFocusable.cs" />
     <Compile Include="Input\IMouseDevice.cs" />
     <Compile Include="Input\IPointerDevice.cs" />