Merge pull request #3255 from AvaloniaUI/refactor/value-store

Make styled property storage typed

src/Avalonia.Animation/Animatable.cs

@@ -65,26 +65,30 @@ public Transitions Transitions
             }
         }
 
-        /// <summary>
-        /// Reacts to a change in a <see cref="AvaloniaProperty"/> value in 
-        /// order to animate the change if a <see cref="ITransition"/> is set for the property.
-        /// </summary>
-        /// <param name="e">The event args.</param>
-        protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs e)
+        protected override void OnPropertyChanged<T>(
+            AvaloniaProperty<T> property,
+            Optional<T> oldValue,
+            BindingValue<T> newValue,
+            BindingPriority priority)
         {
-            if (_transitions is null || _previousTransitions is null || e.Priority == BindingPriority.Animation) return;
+            if (_transitions is null || _previousTransitions is null || priority == BindingPriority.Animation)
+                return;
 
             // PERF-SENSITIVE: Called on every property change. Don't use LINQ here (too many allocations).
             foreach (var transition in _transitions)
             {
-                if (transition.Property == e.Property)
+                if (transition.Property == property)
                 {
-                    if (_previousTransitions.TryGetValue(e.Property, out var dispose))
+                    if (_previousTransitions.TryGetValue(property, out var dispose))
                         dispose.Dispose();
 
-                    var instance = transition.Apply(this, Clock ?? Avalonia.Animation.Clock.GlobalClock, e.OldValue, e.NewValue);
+                    var instance = transition.Apply(
+                        this,
+                        Clock ?? Avalonia.Animation.Clock.GlobalClock,
+                        oldValue.GetValueOrDefault(),
+                        newValue.GetValueOrDefault());
 
-                    _previousTransitions[e.Property] = instance;
+                    _previousTransitions[property] = instance;
                     return;
                 }
             }

src/Avalonia.Base/AttachedProperty.cs

@@ -18,12 +18,14 @@ public class AttachedProperty<TValue> : StyledProperty<TValue>
         /// <param name="ownerType">The class that is registering the property.</param>
         /// <param name="metadata">The property metadata.</param>
         /// <param name="inherits">Whether the property inherits its value.</param>
+        /// <param name="validate">A value validation callback.</param>
         public AttachedProperty(
             string name,
-            Type ownerType,            
+            Type ownerType,
             StyledPropertyMetadata<TValue> metadata,
-            bool inherits = false)
-            : base(name, ownerType, metadata, inherits)
+            bool inherits = false,
+            Func<TValue, bool> validate = null)
+            : base(name, ownerType, metadata, inherits, validate)
         {
         }