From e83c2e06fd6173abe697fe7d2bc22a87035067ef Mon Sep 17 00:00:00 2001
From: Steven Kirk <grokys@gmail.com>
Date: Mon, 25 May 2015 20:07:24 +0200
Subject: [PATCH 1/2] Make sure bound property is registered.

---
 Perspex.Base/PerspexObject.cs                      |  8 ++++++++
 Tests/Perspex.Base.UnitTests/PerspexObjectTests.cs | 11 +++++++++++
 2 files changed, 19 insertions(+)

diff --git a/Perspex.Base/PerspexObject.cs b/Perspex.Base/PerspexObject.cs
index 5fb57a7bac..f43bbcd9aa 100644
--- a/Perspex.Base/PerspexObject.cs
+++ b/Perspex.Base/PerspexObject.cs
@@ -574,6 +574,14 @@ namespace Perspex
             PriorityValue v;
             IDescription description = source as IDescription;
 
+            if (!this.IsRegistered(property))
+            {
+                throw new InvalidOperationException(string.Format(
+                    "Property '{0}' not registered on '{1}'",
+                    property.Name,
+                    this.GetType()));
+            }
+
             if (!this.values.TryGetValue(property, out v))
             {
                 v = this.CreatePriorityValue(property);
diff --git a/Tests/Perspex.Base.UnitTests/PerspexObjectTests.cs b/Tests/Perspex.Base.UnitTests/PerspexObjectTests.cs
index 4577059964..0ceeaee616 100644
--- a/Tests/Perspex.Base.UnitTests/PerspexObjectTests.cs
+++ b/Tests/Perspex.Base.UnitTests/PerspexObjectTests.cs
@@ -355,6 +355,17 @@ namespace Perspex.Base.UnitTests
             Assert.Equal("initial", target.GetValue(Class1.FooProperty));
         }
 
+        [Fact]
+        public void Bind_Throws_Exception_For_Unregistered_Property()
+        {
+            Class1 target = new Class1();
+
+            Assert.Throws<InvalidOperationException>(() =>
+            {
+                target.Bind(Class2.BarProperty, Observable.Return("foo"));
+            });
+        }
+
         [Fact]
         public void Bind_Sets_Subsequent_Value()
         {

From 268b34e4fc329bb110533ee29bed4af2206de8f0 Mon Sep 17 00:00:00 2001
From: Steven Kirk <grokys@gmail.com>
Date: Mon, 25 May 2015 20:09:53 +0200
Subject: [PATCH 2/2] Make TextBlock properties attached properties.

This is how they should've been all along, except PerspexObject.Bind
didn't check that a property was registered before binding to it, so it
went unnoticed.
---
 Perspex.Controls/TextBlock.cs | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/Perspex.Controls/TextBlock.cs b/Perspex.Controls/TextBlock.cs
index 3ed165e624..7c03c3fdd7 100644
--- a/Perspex.Controls/TextBlock.cs
+++ b/Perspex.Controls/TextBlock.cs
@@ -17,19 +17,19 @@ namespace Perspex.Controls
             Border.BackgroundProperty.AddOwner<TextBlock>();
 
         public static readonly PerspexProperty<string> FontFamilyProperty =
-            PerspexProperty.Register<TextBlock, string>("FontFamily", inherits: true);
+            PerspexProperty.RegisterAttached<TextBlock, Control, string>("FontFamily", inherits: true);
 
         public static readonly PerspexProperty<double> FontSizeProperty =
-            PerspexProperty.Register<TextBlock, double>("FontSize", inherits: true);
+            PerspexProperty.RegisterAttached<TextBlock, Control, double>("FontSize", inherits: true);
 
         public static readonly PerspexProperty<FontStyle> FontStyleProperty =
-            PerspexProperty.Register<TextBlock, FontStyle>("FontStyle", inherits: true);
+            PerspexProperty.RegisterAttached<TextBlock, Control, FontStyle>("FontStyle", inherits: true);
 
         public static readonly PerspexProperty<FontWeight> FontWeightProperty =
-            PerspexProperty.Register<TextBlock, FontWeight>("FontWeight", inherits: true, defaultValue: FontWeight.Normal);
+            PerspexProperty.RegisterAttached<TextBlock, Control, FontWeight>("FontWeight", inherits: true, defaultValue: FontWeight.Normal);
 
         public static readonly PerspexProperty<Brush> ForegroundProperty =
-            PerspexProperty.Register<TextBlock, Brush>("Foreground", new SolidColorBrush(0xff000000), inherits: true);
+            PerspexProperty.RegisterAttached<TextBlock, Control, Brush>("Foreground", new SolidColorBrush(0xff000000), inherits: true);
 
         public static readonly PerspexProperty<string> TextProperty =
             PerspexProperty.Register<TextBlock, string>("Text");