Allow selection of tree view items.

Perspex/Controls/TreeView.cs

@@ -10,9 +10,15 @@ namespace Perspex.Controls
     using System.Collections;
     using System.Linq;
     using System.Reactive.Linq;
+    using Perspex.Input;
 
     public class TreeView : SelectingItemsControl
     {
+        public TreeView()
+        {
+            this.PointerPressed += this.OnPointerPressed;
+        }
+
         protected override Control CreateItemControlOverride(object item)
         {
             TreeViewItem result = item as TreeViewItem;
@@ -44,5 +50,25 @@ namespace Perspex.Controls
 
             return treeTemplate;
         }
+
+        private void OnPointerPressed(object sender, PointerEventArgs e)
+        {
+            IVisual source = (IVisual)e.Source;
+            ContentPresenter contentPresenter = source.GetVisualAncestor<ContentPresenter>();
+
+            if (contentPresenter != null)
+            {
+                TreeViewItem item = contentPresenter.TemplatedParent as TreeViewItem;
+
+                if (item != null)
+                {
+                    foreach (var i in this.GetVisualDescendents().OfType<TreeViewItem>())
+                    {
+                        i.IsSelected = i == item;
+                    }
+                }
+            }
+
+        }
     }
 }

Perspex/Controls/TreeViewItem.cs

@@ -11,14 +11,29 @@ namespace Perspex.Controls
         public static readonly PerspexProperty<bool> IsExpandedProperty =
             PerspexProperty.Register<TreeViewItem, bool>("IsExpanded");
 
+        public static readonly PerspexProperty<bool> IsSelectedProperty =
+            PerspexProperty.Register<TreeViewItem, bool>("IsSelected");
+
         TreeView parent;
 
+        public TreeViewItem()
+        {
+            this.AddPseudoClass(IsSelectedProperty, ":selected");
+            AffectsRender(IsSelectedProperty);
+        }
+
         public bool IsExpanded
         {
             get { return this.GetValue(IsExpandedProperty); }
             set { this.SetValue(IsExpandedProperty, value); }
         }
 
+        public bool IsSelected
+        {
+            get { return this.GetValue(IsSelectedProperty); }
+            set { this.SetValue(IsSelectedProperty, value); }
+        }
+
         protected override Control CreateItemControlOverride(object item)
         {
             if (this.parent != null)

Perspex/Themes/Default/TreeViewItemStyle.cs

@@ -26,6 +26,14 @@ namespace Perspex.Themes.Default
                         new Setter(Button.TemplateProperty, ControlTemplate.Create<TreeViewItem>(this.Template)),
                     },
                 },
+                new Style(x => x.OfType<TreeViewItem>().Class(":selected").Template().OfType<ContentPresenter>())
+                {
+                    Setters = new[]
+                    {
+                        new Setter(TreeViewItem.BackgroundProperty, new SolidColorBrush(0xff086f9e)),
+                        new Setter(TreeViewItem.ForegroundProperty, Brushes.White),
+                    },
+                },
                 new Style(x => x.OfType<TreeViewItem>().Template().OfType<ToggleButton>().Class("expander"))
                 {
                     Setters = new[]
@@ -65,6 +73,7 @@ namespace Perspex.Themes.Default
                             },
                             new ContentPresenter
                             {
+                                [~ContentPresenter.BackgroundProperty] = control[~TreeViewItem.BackgroundProperty],
                                 [Grid.ColumnProperty] = 1,
                                 [~ContentPresenter.ContentProperty] = control[~TreeViewItem.HeaderProperty],
                             },

Perspex/Themes/Default/TreeViewStyle.cs

@@ -33,6 +33,7 @@ namespace Perspex.Themes.Default
         {
             return new Border
             {
+                Padding = new Thickness(4),
                 [~Border.BackgroundProperty] = control[~TreeView.BackgroundProperty],
                 [~Border.BorderBrushProperty] = control[~TreeView.BorderBrushProperty],
                 [~Border.BorderThicknessProperty] = control[~TreeView.BorderThicknessProperty],

TestApplication/Program.cs

@@ -180,7 +180,6 @@ namespace TestApplication
                                 HorizontalAlignment = HorizontalAlignment.Center,
                                 VerticalAlignment = VerticalAlignment.Center,
                                 Gap = 8,
-                                Width = 120,
                                 Children = new Controls
                                 {
                                     new TreeView