Make focus adorner styleable.

Perspex.Controls/AdornerTemplate.cs

@@ -0,0 +1,27 @@
+// -----------------------------------------------------------------------
+// <copyright file="AdornerTemplate.cs" company="Steven Kirk">
+// Copyright 2014 MIT Licence. See licence.md for more information.
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace Perspex.Controls
+{
+    using System;
+
+    public class AdornerTemplate
+    {
+        private Func<Control> build;
+
+        public AdornerTemplate(Func<Control> build)
+        {
+            Contract.Requires<NullReferenceException>(build != null);
+
+            this.build = build;
+        }
+
+        public Control Build()
+        {
+            return this.build();
+        }
+    }
+}

Perspex.Controls/Control.cs

@@ -25,6 +25,9 @@ namespace Perspex.Controls
         public static readonly PerspexProperty<object> DataContextProperty =
             PerspexProperty.Register<Control, object>("DataContext", inherits: true);
 
+        public static readonly PerspexProperty<AdornerTemplate> FocusAdornerProperty =
+            PerspexProperty.Register<Control, AdornerTemplate>("FocusAdorner");
+
         public static readonly PerspexProperty<Control> ParentProperty =
             PerspexProperty.Register<Control, Control>("Parent");
 
@@ -43,7 +46,7 @@ namespace Perspex.Controls
 
         private DataTemplates dataTemplates;
 
-        private Rectangle focusAdorner;
+        private Control focusAdorner;
 
         private string id;
 
@@ -199,15 +202,21 @@ namespace Perspex.Controls
 
                 if (adornerLayer != null)
                 {
-                    this.focusAdorner = new Rectangle
+                    if (this.focusAdorner == null)
+                    {
+                        var template = this.GetValue(FocusAdornerProperty);
+
+                        if (template != null)
+                        {
+                            this.focusAdorner = template.Build();
+                        }
+                    }
+
+                    if (this.focusAdorner != null)
                     {
-                        Stroke = Brushes.Black,
-                        StrokeThickness = 1,
-                        StrokeDashArray = new PerspexList<double>(1, 2),
-                        Margin = new Thickness(3),
-                    };
-                    AdornerLayer.SetAdornedElement(this.focusAdorner, this);
-                    adornerLayer.Children.Add(this.focusAdorner);
+                        AdornerLayer.SetAdornedElement(this.focusAdorner, this);
+                        adornerLayer.Children.Add(this.focusAdorner);
+                    }
                 }
             }
         }

Perspex.Controls/Perspex.Controls.csproj

@@ -36,6 +36,7 @@
   <ItemGroup>
     <Compile Include="Border.cs" />
     <Compile Include="Button.cs" />
+    <Compile Include="AdornerTemplate.cs" />
     <Compile Include="DropDown.cs" />
     <Compile Include="IContentControl.cs" />
     <Compile Include="IItemsPanel.cs" />

Perspex.Styling/Selectors.cs

@@ -75,6 +75,17 @@ namespace Perspex.Styling
             };
         }
 
+        public static Selector Is<T>(this Selector previous) where T : IStyleable
+        {
+            Contract.Requires<ArgumentNullException>(previous != null);
+
+            return new Selector(previous)
+            {
+                GetObservable = control => Observable.Return(control is T),
+                SelectorString = ":is(" + typeof(T).Name + ")",
+            };
+        }
+
         public static Selector OfType(this Selector previous, Type type)
         {
             Contract.Requires<ArgumentNullException>(previous != null);

Perspex.Themes.Default/DefaultTheme.cs

@@ -16,6 +16,7 @@ namespace Perspex.Themes.Default
             this.Add(new CheckBoxStyle());
             this.Add(new ContentControlStyle());
             this.Add(new DropDownStyle());
+            this.Add(new FocusAdornerStyle());
             this.Add(new GridSplitterStyle());
             this.Add(new ItemsControlStyle());
             this.Add(new ListBoxStyle());

Perspex.Themes.Default/FocusAdornerStyle.cs

@@ -0,0 +1,42 @@
+// -----------------------------------------------------------------------
+// <copyright file="FocusAdornerStyle.cs" company="Steven Kirk">
+// Copyright 2014 MIT Licence. See licence.md for more information.
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace Perspex.Themes.Default
+{
+    using Perspex.Collections;
+    using Perspex.Controls;
+    using Perspex.Controls.Shapes;
+    using Perspex.Media;
+    using Perspex.Styling;
+
+    public class FocusAdornerStyle : Styles
+    {
+        public FocusAdornerStyle()
+        {
+            this.AddRange(new[]
+            {
+                new Style(x => x.Is<Control>())
+                {
+                    Setters = new[]
+                    {
+                        new Setter(Control.FocusAdornerProperty, new AdornerTemplate(this.Template)),
+                    },
+                },
+            });
+        }
+
+        private Control Template()
+        {
+            return new Rectangle
+            {
+                Stroke = Brushes.Black,
+                StrokeThickness = 1,
+                StrokeDashArray = new PerspexList<double>(1, 2),
+                Margin = new Thickness(3),
+            };
+        }
+    }
+}

Perspex.Themes.Default/Perspex.Themes.Default.csproj

@@ -70,6 +70,7 @@
     </ProjectReference>
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="FocusAdornerStyle.cs" />
     <Compile Include="DropDownStyle.cs" />
     <Compile Include="RadioButtonStyle.cs" />
     <Compile Include="ToggleButtonStyle.cs" />