diff --git a/Perspex.UnitTests/Perspex.UnitTests.csproj b/Perspex.UnitTests/Perspex.UnitTests.csproj
index 4fe2bb0fa6..33ff73f5aa 100644
--- a/Perspex.UnitTests/Perspex.UnitTests.csproj
+++ b/Perspex.UnitTests/Perspex.UnitTests.csproj
@@ -65,7 +65,6 @@
     <Compile Include="PerspexPropertyTests.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="PerspexObjectTests.cs" />
-    <Compile Include="Style.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\Perspex\Perspex.csproj">
diff --git a/Perspex.UnitTests/PerspexObjectTests.cs b/Perspex.UnitTests/PerspexObjectTests.cs
index 8889fb2a05..b222fbc760 100644
--- a/Perspex.UnitTests/PerspexObjectTests.cs
+++ b/Perspex.UnitTests/PerspexObjectTests.cs
@@ -243,6 +243,18 @@ namespace Perspex.UnitTests
             Assert.AreEqual("initial", target.GetValue(Class1.FooProperty));
         }
 
+        [TestMethod]
+        public void Binding_NonGeneric_Sets_Current_Value()
+        {
+            Class1 target = new Class1();
+            Class1 source = new Class1();
+
+            source.SetValue(Class1.FooProperty, "initial");
+            target.SetValue((PerspexProperty)Class1.FooProperty, source.GetObservable(Class1.FooProperty));
+
+            Assert.AreEqual("initial", target.GetValue(Class1.FooProperty));
+        }
+
         [TestMethod]
         public void Binding_Sets_Subsequent_Value()
         {
diff --git a/Perspex.UnitTests/PerspexPropertyTests.cs b/Perspex.UnitTests/PerspexPropertyTests.cs
index 3e1a24e6f2..76e4f5873c 100644
--- a/Perspex.UnitTests/PerspexPropertyTests.cs
+++ b/Perspex.UnitTests/PerspexPropertyTests.cs
@@ -22,7 +22,7 @@ namespace Perspex.UnitTests
                 false);
 
             Assert.AreEqual("test", target.Name);
-            Assert.AreEqual(typeof(string), target.ValueType);
+            Assert.AreEqual(typeof(string), target.PropertyType);
             Assert.AreEqual(typeof(Class1), target.OwnerType);
             Assert.AreEqual(false, target.Inherits);
         }
diff --git a/Perspex.UnitTests/Style.cs b/Perspex.UnitTests/Style.cs
deleted file mode 100644
index 653e69defc..0000000000
--- a/Perspex.UnitTests/Style.cs
+++ /dev/null
@@ -1,91 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Reactive.Disposables;
-using System.Reactive.Linq;
-using System.Text;
-using System.Threading.Tasks;
-using Perspex.Controls;
-
-namespace Perspex
-{
-    public class Style
-    {
-        private bool applied;
-
-        public Style()
-        {
-            this.Setters = new List<Setter>();
-        }
-
-        public Func<Control, Match> Selector
-        {
-            get;
-            set;
-        }
-
-        public IEnumerable<Setter> Setters
-        {
-            get;
-            set;
-        }
-
-        public void Attach(Control control)
-        {
-            Match match = this.Selector(control);
-
-            if (match != null)
-            {
-                List<IObservable<bool>> o = new List<IObservable<bool>>();
-                
-                while (match != null)
-                {
-                    if (match.Observable != null)
-                    {
-                        o.Add(match.Observable);
-                    }
-
-                    match = match.Previous;
-                }
-
-                Observable.CombineLatest(o).Subscribe(x =>
-                {
-                    if (x.All(y => y))
-                    {
-                        this.Apply(control);
-                    }
-                    else if (this.applied)
-                    {
-                        this.Unapply(control);
-                    }
-                });
-            }
-        }
-        
-        private void Apply(Control control)
-        {
-            if (this.Setters != null)
-            {
-                foreach (Setter setter in this.Setters)
-                {
-                    setter.Apply(control);
-                }
-            }
-
-            this.applied = true;
-        }
-
-        private void Unapply(Control control)
-        {
-            if (this.Setters != null)
-            {
-                foreach (Setter setter in this.Setters)
-                {
-                    setter.Unapply(control);
-                }
-
-                this.applied = false;
-            }
-        }
-    }
-}
diff --git a/Perspex/PerspexObject.cs b/Perspex/PerspexObject.cs
index 9075e1ad80..dc250c08b5 100644
--- a/Perspex/PerspexObject.cs
+++ b/Perspex/PerspexObject.cs
@@ -10,6 +10,7 @@ namespace Perspex
     using System.Collections.Generic;
     using System.Diagnostics.Contracts;
     using System.Linq;
+    using System.Linq.Expressions;
     using System.Reactive;
     using System.Reactive.Linq;
     using System.Reflection;
@@ -42,8 +43,8 @@ namespace Perspex
         /// <summary>
         /// The current bindings on this object.
         /// </summary>
-        private Dictionary<PerspexProperty, IDisposable> bindings =
-            new Dictionary<PerspexProperty, IDisposable>();
+        private Dictionary<PerspexProperty, Binding> bindings =
+            new Dictionary<PerspexProperty, Binding>();
 
         /// <summary>
         /// Raised when a <see cref="PerspexProperty"/> value changes on this object/
@@ -161,17 +162,17 @@ namespace Perspex
         public void ClearBinding(PerspexProperty property)
         {
             Contract.Requires<NullReferenceException>(property != null);
-            IDisposable binding;
+            Binding binding;
 
             if (this.bindings.TryGetValue(property, out binding))
             {
-                binding.Dispose();
+                binding.Dispose.Dispose();
                 this.bindings.Remove(property);
             }
         }
 
         /// <summary>
-        /// Clears a <see cref="PerspexProperty"/> value, including its bindings.
+        /// Clears a <see cref="PerspexProperty"/> value, including its binding.
         /// </summary>
         /// <param name="property">The property.</param>
         public void ClearValue(PerspexProperty property)
@@ -181,6 +182,46 @@ namespace Perspex
             this.values.Remove(property);
         }
 
+        /// <summary>
+        /// Clears a binding on a <see cref="PerspexProperty"/>, returning the bound observable and
+        /// leaving the last bound value in place.
+        /// </summary>
+        /// <param name="property">The property.</param>
+        public IObservable<object> ExtractBinding(PerspexProperty property)
+        {
+            Binding binding;
+
+            if (this.bindings.TryGetValue(property, out binding))
+            {
+                this.bindings.Remove(property);
+                return (IObservable<object>)binding.Observable;
+            }
+            else
+            {
+                return null;
+            }
+        }
+
+        /// <summary>
+        /// Clears a binding on a <see cref="PerspexProperty"/>, returning the bound observable and
+        /// leaving the last bound value in place.
+        /// </summary>
+        /// <param name="property">The property.</param>
+        public IObservable<T> ExtractBinding<T>(PerspexProperty<T> property)
+        {
+            Binding binding;
+
+            if (this.bindings.TryGetValue(property, out binding))
+            {
+                this.bindings.Remove(property);
+                return (IObservable<T>)binding.Observable;
+            }
+            else
+            {
+                return null;
+            }
+        }
+
         /// <summary>
         /// Gets an observable for a <see cref="PerspexProperty"/>.
         /// </summary>
@@ -335,8 +376,40 @@ namespace Perspex
         {
             Contract.Requires<NullReferenceException>(property != null);
 
+            TypeInfo typeInfo = value.GetType().GetTypeInfo();
+            Type observableType = typeInfo.ImplementedInterfaces.FirstOrDefault(x =>
+              x.IsConstructedGenericType &&
+              x.GetGenericTypeDefinition() == typeof(IObservable<>));
+
             this.ClearBinding(property);
-            this.SetValueImpl(property, value);
+
+            if (observableType == null)
+            {
+                this.SetValueImpl(property, value);
+            }
+            else
+            {
+                IObservable<object> observable = value as IObservable<object>;
+
+                if (observable == null)
+                {
+                    MethodInfo cast = typeof(PerspexObject).GetTypeInfo()
+                        .DeclaredMethods
+                        .FirstOrDefault(x => x.Name == "CastToObject")
+                        .MakeGenericMethod(observableType.GenericTypeArguments[0]);
+
+                    observable = (IObservable<object>)cast.Invoke(null, new[] { value });
+                }
+
+                this.bindings.Add(property, new Binding
+                {
+                    Observable = value,
+                    Dispose = observable.Subscribe(x =>
+                    {
+                        this.SetValueImpl(property, x);
+                    }),
+                });
+            }
         }
 
         /// <summary>
@@ -362,14 +435,18 @@ namespace Perspex
         {
             Contract.Requires<NullReferenceException>(property != null);
 
-            this.ClearBinding(property);
+            this.SetValue((PerspexProperty)property, source);
+        }
 
-            IDisposable binding = source.Subscribe(value =>
+        private static IObservable<object> CastToObject<T>(IObservable<T> observable)
+        {
+            return Observable.Create<object>(observer =>
             {
-                this.SetValueImpl(property, value);
+                return observable.Subscribe(value =>
+                {
+                    observer.OnNext(value);
+                });
             });
-
-            this.bindings.Add(property, binding);
         }
 
         /// <summary>
@@ -412,6 +489,11 @@ namespace Perspex
         {
             Contract.Requires<NullReferenceException>(property != null);
 
+            if (!property.IsValidType(value))
+            {
+                throw new InvalidOperationException("Invalid value for " + property.Name);
+            }
+
             object oldValue = this.GetValue(property);
 
             if (!object.Equals(oldValue, value))
@@ -420,5 +502,12 @@ namespace Perspex
                 this.RaisePropertyChanged(property, oldValue, value);
             }
         }
+
+        private class Binding
+        {
+            public object Observable { get; set; }
+
+            public IDisposable Dispose { get; set; }
+        }
     }
 }
diff --git a/Perspex/PerspexProperty.cs b/Perspex/PerspexProperty.cs
index 6ec6856ad4..5b1f8e5729 100644
--- a/Perspex/PerspexProperty.cs
+++ b/Perspex/PerspexProperty.cs
@@ -47,7 +47,7 @@ namespace Perspex
             Contract.Requires<NullReferenceException>(ownerType != null);
 
             this.Name = name;
-            this.ValueType = valueType;
+            this.PropertyType = valueType;
             this.OwnerType = ownerType;
             this.Inherits = inherits;
             this.defaultValues.Add(ownerType, defaultValue);
@@ -61,7 +61,7 @@ namespace Perspex
         /// <summary>
         /// Gets the type of the property's value.
         /// </summary>
-        public Type ValueType { get; private set; }
+        public Type PropertyType { get; private set; }
 
         /// <summary>
         /// Gets the type of the class that registers the property.
@@ -125,6 +125,17 @@ namespace Perspex
             return this.defaultValues[this.OwnerType];
         }
 
+        public bool IsValidType(object value)
+        {
+            if (value == null)
+            {
+                return !this.PropertyType.GetTypeInfo().IsValueType ||
+                    Nullable.GetUnderlyingType(this.PropertyType) != null;
+            }
+
+            return this.PropertyType.GetTypeInfo().IsAssignableFrom(value.GetType().GetTypeInfo());
+        }
+
         /// <summary>
         /// Gets the default value for the property on the specified type.
         /// </summary>
diff --git a/Perspex/Setter.cs b/Perspex/Setter.cs
index bcf758c275..e9e1743dd2 100644
--- a/Perspex/Setter.cs
+++ b/Perspex/Setter.cs
@@ -7,9 +7,44 @@
 namespace Perspex
 {
     using System;
+    using System.Collections.Generic;
     using System.Diagnostics.Contracts;
+    using System.Reactive.Disposables;
     using Perspex.Controls;
 
+    internal class SetterSubject : IObservable<object>
+    {
+        private Control control;
+
+        private object onValue;
+
+        private object offValue;
+
+        private List<IObserver<object>> observers;
+
+        public SetterSubject(Control control, object onValue, object offValue)
+        {
+            this.control = control;
+            this.onValue = onValue;
+            this.offValue = offValue;
+            this.observers = new List<IObserver<object>>();
+        }
+
+        public IDisposable Subscribe(IObserver<object> observer)
+        {
+            observers.Add(observer);
+            return Disposable.Create(() => this.observers.Remove(observer));
+        }
+
+        public void Push(bool on)
+        {
+            foreach (IObserver<object> o in this.observers)
+            {
+                o.OnNext(on ? this.onValue : this.offValue);
+            }
+        }
+    }
+
     public class Setter
     {
         private object oldValue;
@@ -26,19 +61,10 @@ namespace Perspex
             set;
         }
 
-        public void Apply(Control control)
+        internal SetterSubject CreateSubject(Control control)
         {
-            Contract.Requires<NullReferenceException>(control != null);
-
-            this.oldValue = control.GetValue(this.Property);
-            control.SetValue(this.Property, this.Value);
-        }
-
-        public void Unapply(Control control)
-        {
-            Contract.Requires<NullReferenceException>(control != null);
-
-            control.SetValue(this.Property, this.oldValue);
+            object oldValue = control.ExtractBinding(this.Property) ?? control.GetValue(this.Property);
+            return new SetterSubject(control, this.Value, oldValue);
         }
     }
 }
diff --git a/Perspex/Style.cs b/Perspex/Style.cs
index fec4a09324..f56e8ba25a 100644
--- a/Perspex/Style.cs
+++ b/Perspex/Style.cs
@@ -10,6 +10,7 @@ namespace Perspex
     using System.Collections.Generic;
     using System.Linq;
     using System.Reactive.Linq;
+    using System.Reactive.Subjects;
     using Perspex.Controls;
 
     public class Style
@@ -51,43 +52,24 @@ namespace Perspex
                     match = match.Previous;
                 }
 
-                Observable.CombineLatest(o).Subscribe(x =>
-                {
-                    if (x.All(y => y))
-                    {
-                        this.Apply(control);
-                    }
-                    else if (this.applied)
-                    {
-                        this.Unapply(control);
-                    }
-                });
-            }
-        }
-        
-        private void Apply(Control control)
-        {
-            if (this.Setters != null)
-            {
+                List<SetterSubject> subjects = new List<SetterSubject>();
+
                 foreach (Setter setter in this.Setters)
                 {
-                    setter.Apply(control);
+                    SetterSubject subject = setter.CreateSubject(control);
+                    subjects.Add(subject);
+                    control.SetValue(setter.Property, subject);
                 }
-            }
-
-            this.applied = true;
-        }
 
-        private void Unapply(Control control)
-        {
-            if (this.Setters != null)
-            {
-                foreach (Setter setter in this.Setters)
+                Observable.CombineLatest(o).Subscribe(x =>
                 {
-                    setter.Unapply(control);
-                }
+                    bool on = x.All(y => y);
 
-                this.applied = false;
+                    foreach (SetterSubject subject in subjects)
+                    {
+                        subject.Push(on);
+                    }
+                });
             }
         }
     }