Merge pull request #3174 from mstr2/validate-fix

Fixed an issue where ValueStore.Changed could be called with pre-vali…

src/Avalonia.Base/ValueStore.cs

@@ -57,7 +57,8 @@ namespace Avalonia
                 {
                     if (priority == (int)BindingPriority.LocalValue)
                     {
-                        _propertyValues.SetValue(property, Validate(property, value));
+                        Validate(property, ref value);
+                        _propertyValues.SetValue(property, value);
                         Changed(property, priority, v, value);
                         return;
                     }
@@ -78,7 +79,8 @@ namespace Avalonia
 
                 if (priority == (int)BindingPriority.LocalValue)
                 {
-                    _propertyValues.AddValue(property, Validate(property, value));
+                    Validate(property, ref value);
+                    _propertyValues.AddValue(property, value);
                     Changed(property, priority, AvaloniaProperty.UnsetValue, value);
                     return;
                 }
@@ -166,16 +168,14 @@ namespace Avalonia
                 validate2);
         }
 
-        private object Validate(AvaloniaProperty property, object value)
+        private void Validate(AvaloniaProperty property, ref object value)
         {
             var validate = ((IStyledPropertyAccessor)property).GetValidationFunc(_owner.GetType());
 
             if (validate != null && value != AvaloniaProperty.UnsetValue)
             {
-                return validate(_owner, value);
+                value = validate(_owner, value);
             }
-
-            return value;
         }
 
         private DeferredSetter<T> GetDeferredSetter<T>(AvaloniaProperty property)

tests/Avalonia.Base.UnitTests/AvaloniaObjectTests_Validation.cs

@@ -78,6 +78,18 @@ namespace Avalonia.Base.UnitTests
             Assert.Equal(10, target.GetValue(Class1.AttachedProperty));
         }
 
+        [Fact]
+        public void PropertyChanged_Event_Uses_Coerced_Value()
+        {
+            var inst = new Class1();
+            inst.PropertyChanged += (sender, e) =>
+            {
+                Assert.Equal(10, e.NewValue);
+            };
+
+            inst.SetValue(Class1.QuxProperty, 15);
+        }
+
         private class Class1 : AvaloniaObject
         {
             public static readonly StyledProperty<int> QuxProperty =