Change the way PriorityValue notifies.

Directly call a Changed method on the PriorityValue owner rather than using an observable.

src/Perspex.Base/IPriorityValueOwner.cs

@@ -0,0 +1,19 @@
+// Copyright (c) The Perspex Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+namespace Perspex
+{
+    /// <summary>
+    /// An owner of a <see cref="PriorityValue"/>.
+    /// </summary>
+    internal interface IPriorityValueOwner
+    {
+        /// <summary>
+        /// Called when a <see cref="PriorityValue"/>'s value changes.
+        /// </summary>
+        /// <param name="sender">The source of the change.</param>
+        /// <param name="oldValue">The old value.</param>
+        /// <param name="newValue">The new value.</param>
+        void Changed(PriorityValue sender, object oldValue, object newValue);
+    }
+}

src/Perspex.Base/Perspex.Base.csproj

@@ -54,6 +54,7 @@
     <Compile Include="Diagnostics\IPerspexObjectDebug.cs" />
     <Compile Include="Diagnostics\PerspexObjectExtensions.cs" />
     <Compile Include="AttachedProperty.cs" />
+    <Compile Include="IPriorityValueOwner.cs" />
     <Compile Include="IStyledPropertyAccessor.cs" />
     <Compile Include="IDirectPropertyAccessor.cs" />
     <Compile Include="DirectProperty.cs" />

src/Perspex.Base/PerspexObject.cs

@@ -21,7 +21,7 @@ namespace Perspex
     /// <remarks>
     /// This class is analogous to DependencyObject in WPF.
     /// </remarks>
-    public class PerspexObject : IPerspexObject, IPerspexObjectDebug, INotifyPropertyChanged
+    public class PerspexObject : IPerspexObject, IPerspexObjectDebug, INotifyPropertyChanged, IPriorityValueOwner
     {
         /// <summary>
         /// Maintains a list of direct property binding subscriptions so that the binding source
@@ -477,6 +477,34 @@ namespace Perspex
             }
         }
 
+        /// <inheritdoc/>
+        void IPriorityValueOwner.Changed(PriorityValue sender, object oldValue, object newValue)
+        {
+            var property = sender.Property;
+            var priority = (BindingPriority)sender.ValuePriority;
+
+            oldValue = (oldValue == PerspexProperty.UnsetValue) ?
+                GetDefaultValue(property) :
+                oldValue;
+            newValue = (newValue == PerspexProperty.UnsetValue) ?
+                GetDefaultValue(property) :
+                newValue;
+
+            if (!Equals(oldValue, newValue))
+            {
+                RaisePropertyChanged(property, oldValue, newValue, priority);
+
+                Logger.Verbose(
+                    LogArea.Property,
+                    this,
+                    "{Property} changed from {$Old} to {$Value} with priority {Priority}",
+                    property,
+                    oldValue,
+                    newValue,
+                    priority);
+            }
+        }
+
         /// <inheritdoc/>
         Delegate[] IPerspexObjectDebug.GetPropertyChangedSubscribers()
         {
@@ -604,34 +632,10 @@ namespace Perspex
 
             PriorityValue result = new PriorityValue(
                 this,
-                property.Name, 
+                property,
                 property.PropertyType, 
                 validate2);
 
-            result.Changed.Subscribe(x =>
-            {
-                object oldValue = (x.Item1 == PerspexProperty.UnsetValue) ?
-                    GetDefaultValue(property) :
-                    x.Item1;
-                object newValue = (x.Item2 == PerspexProperty.UnsetValue) ?
-                    GetDefaultValue(property) :
-                    x.Item2;
-
-                if (!Equals(oldValue, newValue))
-                {
-                    RaisePropertyChanged(property, oldValue, newValue, (BindingPriority)result.ValuePriority);
-
-                    Logger.Verbose(
-                        LogArea.Property, 
-                        this,
-                        "{Property} changed from {$Old} to {$Value} with priority {Priority}",
-                        property, 
-                        oldValue, 
-                        newValue, 
-                        (BindingPriority)result.ValuePriority);
-                }
-            });
-
             return result;
         }
 

src/Perspex.Base/PriorityValue.cs

@@ -20,20 +20,16 @@ namespace Perspex
     /// represent higher priorites. The current <see cref="Value"/> is selected from the highest
     /// priority binding that doesn't return <see cref="PerspexProperty.UnsetValue"/>. Where there
     /// are multiple bindings registered with the same priority, the most recently added binding
-    /// has a higher priority. Each time the value changes, the <see cref="Changed"/> observable is
-    /// fired with the old and new values.
+    /// has a higher priority. Each time the value changes, the 
+    /// <see cref="IPriorityValueOwner.Changed(PerspexProperty, object, object)"/> method on the 
+    /// owner object is fired with the old and new values.
     /// </remarks>
     internal class PriorityValue
     {
         /// <summary>
         /// The owner of the object.
         /// </summary>
-        private readonly PerspexObject _owner;
-
-        /// <summary>
-        /// The name of the property.
-        /// </summary>
-        private readonly string _name;
+        private readonly IPriorityValueOwner _owner;
 
         /// <summary>
         /// The value type.
@@ -45,11 +41,6 @@ namespace Perspex
         /// </summary>
         private readonly Dictionary<int, PriorityLevel> _levels = new Dictionary<int, PriorityLevel>();
 
-        /// <summary>
-        /// The changed observable.
-        /// </summary>
-        private readonly Subject<Tuple<object, object>> _changed = new Subject<Tuple<object, object>>();
-
         /// <summary>
         /// The current value.
         /// </summary>
@@ -64,17 +55,17 @@ namespace Perspex
         /// Initializes a new instance of the <see cref="PriorityValue"/> class.
         /// </summary>
         /// <param name="owner">The owner of the object.</param>
-        /// <param name="name">The name of the property.</param>
+        /// <param name="property">The property that the value represents.</param>
         /// <param name="valueType">The value type.</param>
         /// <param name="validate">An optional validation function.</param>
         public PriorityValue(
-            PerspexObject owner,
-            string name, 
+            IPriorityValueOwner owner,
+            PerspexProperty property, 
             Type valueType,
             Func<object, object> validate = null)
         {
             _owner = owner;
-            _name = name;
+            Property = property;
             _valueType = valueType;
             _value = PerspexProperty.UnsetValue;
             ValuePriority = int.MaxValue;
@@ -82,12 +73,9 @@ namespace Perspex
         }
 
         /// <summary>
-        /// Fired whenever the current <see cref="Value"/> changes.
+        /// Gets the property that the value represents.
         /// </summary>
-        /// <remarks>
-        /// The old and new values may be the same, this class does not check for distinct values.
-        /// </remarks>
-        public IObservable<Tuple<object, object>> Changed => _changed;
+        public PerspexProperty Property { get; }
 
         /// <summary>
         /// Gets the current value.
@@ -236,7 +224,7 @@ namespace Perspex
 
                 ValuePriority = priority;
                 _value = castValue;
-                _changed.OnNext(Tuple.Create(old, _value));
+                _owner?.Changed(this, old, _value);
             }
             else
             {
@@ -244,7 +232,7 @@ namespace Perspex
                     LogArea.Property, 
                     _owner,
                     "Binding produced invalid value for {$Property} ({$PropertyType}): {$Value} ({$ValueType})",
-                    _name, 
+                    Property.Name, 
                     _valueType, 
                     value,
                     value.GetType());

src/Perspex.Base/Properties/AssemblyInfo.cs

@@ -5,4 +5,5 @@ using System.Reflection;
 using System.Runtime.CompilerServices;
 
 [assembly: AssemblyTitle("Perspex.Base")]
-[assembly: InternalsVisibleTo("Perspex.Base.UnitTests")]
+[assembly: InternalsVisibleTo("Perspex.Base.UnitTests")]
+[assembly: InternalsVisibleTo("DynamicProxyGenAssembly2")] 

tests/Perspex.Base.UnitTests/Perspex.Base.UnitTests.csproj

@@ -44,6 +44,10 @@
       <Private>True</Private>
     </Reference>
     <Reference Include="Microsoft.VisualStudio.QualityTools.UnitTestFramework, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL" />
+    <Reference Include="Moq, Version=4.2.1510.2205, Culture=neutral, PublicKeyToken=69f491c39445e920, processorArchitecture=MSIL">
+      <HintPath>..\..\packages\Moq.4.2.1510.2205\lib\net40\Moq.dll</HintPath>
+      <Private>True</Private>
+    </Reference>
     <Reference Include="System" />
     <Reference Include="System.Reactive.Core, Version=2.2.5.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL">
       <HintPath>..\..\packages\Rx-Core.2.2.5\lib\net45\System.Reactive.Core.dll</HintPath>

tests/Perspex.Base.UnitTests/PriorityValueTests.cs

@@ -5,16 +5,23 @@ using System;
 using System.Linq;
 using System.Reactive.Linq;
 using System.Reactive.Subjects;
+using Moq;
 using Xunit;
 
 namespace Perspex.Base.UnitTests
 {
     public class PriorityValueTests
     {
+        private static readonly PerspexProperty TestProperty = 
+            new StyledProperty<string>(
+                "Test", 
+                typeof(PriorityValueTests), 
+                new StyledPropertyMetadata<string>());
+
         [Fact]
         public void Initial_Value_Should_Be_UnsetValue()
         {
-            var target = new PriorityValue(null, "Test", typeof(string));
+            var target = new PriorityValue(null, TestProperty, typeof(string));
 
             Assert.Same(PerspexProperty.UnsetValue, target.Value);
         }
@@ -22,7 +29,7 @@ namespace Perspex.Base.UnitTests
         [Fact]
         public void First_Binding_Sets_Value()
         {
-            var target = new PriorityValue(null, "Test", typeof(string));
+            var target = new PriorityValue(null, TestProperty, typeof(string));
 
             target.Add(Single("foo"), 0);
 
@@ -32,7 +39,7 @@ namespace Perspex.Base.UnitTests
         [Fact]
         public void Changing_Binding_Should_Set_Value()
         {
-            var target = new PriorityValue(null, "Test", typeof(string));
+            var target = new PriorityValue(null, TestProperty, typeof(string));
             var subject = new BehaviorSubject<string>("foo");
 
             target.Add(subject, 0);
@@ -44,7 +51,7 @@ namespace Perspex.Base.UnitTests
         [Fact]
         public void Setting_Direct_Value_Should_Override_Binding()
         {
-            var target = new PriorityValue(null, "Test", typeof(string));
+            var target = new PriorityValue(null, TestProperty, typeof(string));
 
             target.Add(Single("foo"), 0);
             target.SetValue("bar", 0);
@@ -55,7 +62,7 @@ namespace Perspex.Base.UnitTests
         [Fact]
         public void Binding_Firing_Should_Override_Direct_Value()
         {
-            var target = new PriorityValue(null, "Test", typeof(string));
+            var target = new PriorityValue(null, TestProperty, typeof(string));
             var source = new BehaviorSubject<object>("initial");
 
             target.Add(source, 0);
@@ -69,7 +76,7 @@ namespace Perspex.Base.UnitTests
         [Fact]
         public void Earlier_Binding_Firing_Should_Not_Override_Later()
         {
-            var target = new PriorityValue(null, "Test", typeof(string));
+            var target = new PriorityValue(null, TestProperty, typeof(string));
             var nonActive = new BehaviorSubject<object>("na");
             var source = new BehaviorSubject<object>("initial");
 
@@ -85,7 +92,7 @@ namespace Perspex.Base.UnitTests
         [Fact]
         public void Binding_Completing_Should_Revert_To_Direct_Value()
         {
-            var target = new PriorityValue(null, "Test", typeof(string));
+            var target = new PriorityValue(null, TestProperty, typeof(string));
             var source = new BehaviorSubject<object>("initial");
 
             target.Add(source, 0);
@@ -101,7 +108,7 @@ namespace Perspex.Base.UnitTests
         [Fact]
         public void Binding_With_Lower_Priority_Has_Precedence()
         {
-            var target = new PriorityValue(null, "Test", typeof(string));
+            var target = new PriorityValue(null, TestProperty, typeof(string));
 
             target.Add(Single("foo"), 1);
             target.Add(Single("bar"), 0);
@@ -113,7 +120,7 @@ namespace Perspex.Base.UnitTests
         [Fact]
         public void Later_Binding_With_Same_Priority_Should_Take_Precedence()
         {
-            var target = new PriorityValue(null, "Test", typeof(string));
+            var target = new PriorityValue(null, TestProperty, typeof(string));
 
             target.Add(Single("foo"), 1);
             target.Add(Single("bar"), 0);
@@ -126,7 +133,7 @@ namespace Perspex.Base.UnitTests
         [Fact]
         public void Changing_Binding_With_Lower_Priority_Should_Set_Not_Value()
         {
-            var target = new PriorityValue(null, "Test", typeof(string));
+            var target = new PriorityValue(null, TestProperty, typeof(string));
             var subject = new BehaviorSubject<string>("bar");
 
             target.Add(Single("foo"), 0);
@@ -139,7 +146,7 @@ namespace Perspex.Base.UnitTests
         [Fact]
         public void UnsetValue_Should_Fall_Back_To_Next_Binding()
         {
-            var target = new PriorityValue(null, "Test", typeof(string));
+            var target = new PriorityValue(null, TestProperty, typeof(string));
             var subject = new BehaviorSubject<object>("bar");
 
             target.Add(subject, 0);
@@ -155,33 +162,31 @@ namespace Perspex.Base.UnitTests
         [Fact]
         public void Adding_Value_Should_Call_OnNext()
         {
-            var target = new PriorityValue(null, "Test", typeof(string));
-            bool called = false;
+            var owner = new Mock<IPriorityValueOwner>();
+            var target = new PriorityValue(owner.Object, TestProperty, typeof(string));
 
-            target.Changed.Subscribe(value => called = value.Item1 == PerspexProperty.UnsetValue && (string)value.Item2 == "foo");
             target.Add(Single("foo"), 0);
 
-            Assert.True(called);
+            owner.Verify(x => x.Changed(target, PerspexProperty.UnsetValue, "foo"));
         }
 
         [Fact]
         public void Changing_Value_Should_Call_OnNext()
         {
-            var target = new PriorityValue(null, "Test", typeof(string));
+            var owner = new Mock<IPriorityValueOwner>();
+            var target = new PriorityValue(owner.Object, TestProperty, typeof(string));
             var subject = new BehaviorSubject<object>("foo");
-            bool called = false;
 
             target.Add(subject, 0);
-            target.Changed.Subscribe(value => called = (string)value.Item1 == "foo" && (string)value.Item2 == "bar");
             subject.OnNext("bar");
 
-            Assert.True(called);
+            owner.Verify(x => x.Changed(target, "foo", "bar"));
         }
 
         [Fact]
         public void Disposing_A_Binding_Should_Revert_To_Next_Value()
         {
-            var target = new PriorityValue(null, "Test", typeof(string));
+            var target = new PriorityValue(null, TestProperty, typeof(string));
 
             target.Add(Single("foo"), 0);
             var disposable = target.Add(Single("bar"), 0);
@@ -194,7 +199,7 @@ namespace Perspex.Base.UnitTests
         [Fact]
         public void Disposing_A_Binding_Should_Remove_BindingEntry()
         {
-            var target = new PriorityValue(null, "Test", typeof(string));
+            var target = new PriorityValue(null, TestProperty, typeof(string));
 
             target.Add(Single("foo"), 0);
             var disposable = target.Add(Single("bar"), 0);
@@ -207,7 +212,7 @@ namespace Perspex.Base.UnitTests
         [Fact]
         public void Completing_A_Binding_Should_Revert_To_Previous_Binding()
         {
-            var target = new PriorityValue(null, "Test", typeof(string));
+            var target = new PriorityValue(null, TestProperty, typeof(string));
             var source = new BehaviorSubject<object>("bar");
 
             target.Add(Single("foo"), 0);
@@ -221,7 +226,7 @@ namespace Perspex.Base.UnitTests
         [Fact]
         public void Completing_A_Binding_Should_Revert_To_Lower_Priority()
         {
-            var target = new PriorityValue(null, "Test", typeof(string));
+            var target = new PriorityValue(null, TestProperty, typeof(string));
             var source = new BehaviorSubject<object>("bar");
 
             target.Add(Single("foo"), 1);
@@ -235,7 +240,7 @@ namespace Perspex.Base.UnitTests
         [Fact]
         public void Completing_A_Binding_Should_Remove_BindingEntry()
         {
-            var target = new PriorityValue(null, "Test", typeof(string));
+            var target = new PriorityValue(null, TestProperty, typeof(string));
             var subject = new BehaviorSubject<object>("bar");
 
             target.Add(Single("foo"), 0);
@@ -249,7 +254,7 @@ namespace Perspex.Base.UnitTests
         [Fact]
         public void Direct_Value_Should_Be_Coerced()
         {
-            var target = new PriorityValue(null, "Test", typeof(int), x => Math.Min((int)x, 10));
+            var target = new PriorityValue(null, TestProperty, typeof(int), x => Math.Min((int)x, 10));
 
             target.SetValue(5, 0);
             Assert.Equal(5, target.Value);
@@ -260,7 +265,7 @@ namespace Perspex.Base.UnitTests
         [Fact]
         public void Bound_Value_Should_Be_Coerced()
         {
-            var target = new PriorityValue(null, "Test", typeof(int), x => Math.Min((int)x, 10));
+            var target = new PriorityValue(null, TestProperty, typeof(int), x => Math.Min((int)x, 10));
             var source = new Subject<object>();
 
             target.Add(source, 0);
@@ -274,7 +279,7 @@ namespace Perspex.Base.UnitTests
         public void Revalidate_Should_ReCoerce_Value()
         {
             var max = 10;
-            var target = new PriorityValue(null, "Test", typeof(int), x => Math.Min((int)x, max));
+            var target = new PriorityValue(null, TestProperty, typeof(int), x => Math.Min((int)x, max));
             var source = new Subject<object>();
 
             target.Add(source, 0);

tests/Perspex.Base.UnitTests/packages.config

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
+  <package id="Moq" version="4.2.1510.2205" targetFramework="net45" />
   <package id="Rx-Core" version="2.2.5" targetFramework="net45" />
   <package id="Rx-Interfaces" version="2.2.5" targetFramework="net45" />
   <package id="Rx-Linq" version="2.2.5" targetFramework="net45" />