Added TemplateBinding syntactic sugar.

Perspex.UnitTests/Controls/ContentControlTests.cs

@@ -71,10 +71,7 @@ namespace Perspex.UnitTests.Controls
                 Border border = new Border();
                 border.Background = new Perspex.Media.SolidColorBrush(0xffffffff);
                 ContentPresenter contentPresenter = new ContentPresenter();
-                contentPresenter.Bind(
+                contentPresenter.TemplateBinding(parent, ContentPresenter.ContentProperty);
-                    ContentPresenter.ContentProperty, 
-                    parent.GetObservable(ContentControl.ContentProperty),
-                    BindingPriority.TemplatedParent);
                 border.Content = contentPresenter;
                 return border;
             });

Perspex.UnitTests/Styling/TestControlBase.cs

@@ -30,7 +30,7 @@ namespace Perspex.UnitTests.Styling
             set;
         }
 
-        public void Bind(PerspexProperty property, IObservable<object> source, BindingPriority priority = BindingPriority.LocalValue)
+        public IDisposable Bind(PerspexProperty property, IObservable<object> source, BindingPriority priority = BindingPriority.LocalValue)
         {
             throw new NotImplementedException();
         }

Perspex.UnitTests/Styling/TestTemplatedControl.cs

@@ -38,7 +38,7 @@ namespace Perspex.UnitTests.Styling
             throw new NotImplementedException();
         }
 
-        public void Bind(PerspexProperty property, IObservable<object> source, BindingPriority priority = BindingPriority.LocalValue)
+        public IDisposable Bind(PerspexProperty property, IObservable<object> source, BindingPriority priority = BindingPriority.LocalValue)
         {
             throw new NotImplementedException();
         }

Perspex/BindingExtensions.cs

@@ -0,0 +1,39 @@
+// -----------------------------------------------------------------------
+// <copyright file="BindingExtensions.cs" company="Steven Kirk">
+// Copyright 2014 MIT Licence. See licence.md for more information.
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace Perspex
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Linq;
+    using System.Text;
+    using System.Threading.Tasks;
+using Perspex.Controls;
+
+    /// <summary>
+    /// Provides binding utility extension methods.
+    /// </summary>
+    public static class BindingExtensions
+    {
+        /// <summary>
+        /// Binds a property in a template to the same property in the templated parent.
+        /// </summary>
+        /// <typeparam name="T">The property type.</typeparam>
+        /// <param name="o">The control in the template.</param>
+        /// <param name="templatedParent">The templated parent.</param>
+        /// <param name="property">The property.</param>
+        /// <returns>
+        /// A disposable which can be used to terminate the binding.
+        /// </returns>
+        public static IDisposable TemplateBinding<T>(
+            this PerspexObject o,
+            ITemplatedControl templatedParent,
+            PerspexProperty<T> property)
+        {
+            return o.Bind(property, templatedParent.GetObservable(property), BindingPriority.TemplatedParent);
+        }
+    }
+}

Perspex/Perspex.csproj

@@ -69,6 +69,7 @@
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="Application.cs" />
+    <Compile Include="BindingExtensions.cs" />
     <Compile Include="Styling\StyleBinding.cs" />
     <Compile Include="Classes.cs" />
     <Compile Include="Contract.cs" />

Perspex/PerspexObject.cs

@@ -417,6 +417,13 @@ namespace Perspex
                 this.values.Add(property, v);
             }
 
+            this.Log().Debug(string.Format(
+                "Set local value of {0}.{1} (#{2:x8}) to {3}",
+                this.GetType().Name,
+                property.Name,
+                this.GetHashCode(),
+                value));
+
             v.Clear(priority);
             v.Add(Observable.Never<object>().StartWith(value), priority);
         }
@@ -441,7 +448,10 @@ namespace Perspex
         /// <param name="property">The property.</param>
         /// <param name="source">The observable.</param>
         /// <param name="priority">The priority of the binding.</param>
-        public void Bind(
+        /// <returns>
+        /// A disposable which can be used to terminate the binding.
+        /// </returns>
+        public IDisposable Bind(
             PerspexProperty property,
             IObservable<object> source,
             BindingPriority priority = BindingPriority.LocalValue)
@@ -449,6 +459,7 @@ namespace Perspex
             Contract.Requires<NullReferenceException>(property != null);
 
             PriorityValue v;
+            IObservableDescription description = source as IObservableDescription;
 
             if (!this.values.TryGetValue(property, out v))
             {
@@ -461,13 +472,14 @@ namespace Perspex
                 v.Clear((int)priority);
             }
 
-            v.Add(source, (int)priority);
-
             this.Log().Debug(string.Format(
-                "Bound value of {0}.{1} (#{2:x8})",
+                "Bound value of {0}.{1} (#{2:x8}) to {3}",
                 this.GetType().Name,
                 property.Name,
-                this.GetHashCode()));
+                this.GetHashCode(),
+                description != null ? description.Description : "[Anonymous]"));
+
+            return v.Add(source, (int)priority);
         }
 
         /// <summary>
@@ -477,14 +489,17 @@ namespace Perspex
         /// <param name="property">The property.</param>
         /// <param name="source">The observable.</param>
         /// <param name="priority">The priority of the binding.</param>
-        public void Bind<T>(
+        /// <returns>
+        /// A disposable which can be used to terminate the binding.
+        /// </returns>
+        public IDisposable Bind<T>(
             PerspexProperty<T> property, 
             IObservable<T> source, 
             BindingPriority priority = BindingPriority.LocalValue)
         {
             Contract.Requires<NullReferenceException>(property != null);
 
-            this.Bind((PerspexProperty)property, (IObservable<object>)source, priority);
+            return this.Bind((PerspexProperty)property, (IObservable<object>)source, priority);
         }
 
         private PriorityValue CreatePriorityValue(PerspexProperty property)
@@ -505,10 +520,11 @@ namespace Perspex
                     this.RaisePropertyChanged(property, oldValue, newValue);
 
                     this.Log().Debug(string.Format(
-                        "Set value of {0}.{1} (#{2:x8}) to {3}",
+                        "Value of {0}.{1} (#{2:x8}) changed from {3} to {4}",
                         this.GetType().Name,
                         property.Name,
                         this.GetHashCode(),
+                        oldValue,
                         newValue));
                 }
             });

Perspex/Styling/IStyleable.cs

@@ -36,7 +36,10 @@ namespace Perspex.Styling
         /// <param name="property">The property.</param>
         /// <param name="source">The observable.</param>
         /// <param name="priority">The priority of the binding.</param>
-        void Bind(
+        /// <returns>
+        /// A disposable which can be used to terminate the binding.
+        /// </returns>
+        IDisposable Bind(
             PerspexProperty property, 
             IObservable<object> source, 
             BindingPriority priority = BindingPriority.LocalValue);

Perspex/Themes/Default/ButtonStyle.cs

@@ -56,16 +56,10 @@ namespace Perspex.Themes.Default
             Border border = new Border();
             border.Id = "border";
             border.Padding = new Thickness(3);
-            border.Bind(
+            border.TemplateBinding(control, Border.BackgroundProperty);
-                Border.BackgroundProperty,
-                control.GetObservable(Button.BackgroundProperty),
-                BindingPriority.TemplatedParent);
 
             ContentPresenter contentPresenter = new ContentPresenter();
-            contentPresenter.Bind(
+            contentPresenter.TemplateBinding(control, ContentPresenter.ContentProperty);
-                ContentPresenter.ContentProperty, 
-                control.GetObservable(Button.ContentProperty),
-                BindingPriority.TemplatedParent);
 
             border.Content = contentPresenter;
             return border;