Fixed AmbiguousMatchException in DataAnnotationsValidator for Hidden Members

src/Components/Forms/src/EditContextDataAnnotationsExtensions.cs

@@ -367,7 +367,16 @@ private static bool TryGetValidatableProperty(in FieldIdentifier fieldIdentifier
             {
                 // DataAnnotations only validates public properties, so that's all we'll look for
                 // If we can't find it, cache 'null' so we don't have to try again next time
-                propertyInfo = cacheKey.ModelType.GetProperty(cacheKey.FieldName);
+                propertyInfo = cacheKey.ModelType.GetProperty(
+                    cacheKey.FieldName,
+                    BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly);
+
+                if (propertyInfo is null)
+                {
+                    propertyInfo = cacheKey.ModelType.GetProperty(
+                        cacheKey.FieldName,
+                        BindingFlags.Public | BindingFlags.Instance | BindingFlags.FlattenHierarchy);
+                }
 
                 // No need to lock, because it doesn't matter if we write the same value twice
                 _propertyInfoCache[cacheKey] = propertyInfo;

src/Components/Forms/test/EditContextDataAnnotationsExtensionsTest.cs

@@ -170,6 +170,110 @@ public void CanDetachFromEditContext()
         Assert.Empty(editContext.GetValidationMessages());
     }
 
+    [Fact]
+    public void ValidatesHiddenPropertiesWithoutAmbiguousMatchException()
+    {
+        var model = new DerivedModelWithHiddenProperty { OrderID = 150 };
+        var editContext = new EditContext(model);
+        editContext.EnableDataAnnotationsValidation(_serviceProvider);
+
+        Assert.False(editContext.Validate());
+        Assert.Equal(new[] { "OrderID:range" }, editContext.GetValidationMessages());
+
+        var orderIdIdentifier = new FieldIdentifier(model, nameof(DerivedModelWithHiddenProperty.OrderID));
+        editContext.NotifyFieldChanged(orderIdIdentifier);
+        model.OrderID = 50;
+        editContext.NotifyFieldChanged(orderIdIdentifier);
+        Assert.Empty(editContext.GetValidationMessages());
+    }
+
+    [Fact]
+    public void ValidatesHiddenPropertiesWithPropertyCaching()
+    {
+        var model = new DerivedModelWithHiddenProperty { OrderID = 150 };
+        var editContext = new EditContext(model);
+        editContext.EnableDataAnnotationsValidation(_serviceProvider);
+        var orderIdIdentifier = new FieldIdentifier(model, nameof(DerivedModelWithHiddenProperty.OrderID));
+
+        var sequence = new[] { 150, 50, 200, 75, 99, 101, 1 };
+        var expected = new[] { "OrderID:range" };
+        foreach (var value in sequence)
+        {
+            model.OrderID = value;
+            editContext.NotifyFieldChanged(orderIdIdentifier);
+            var expectedMessages = (value < 1 || value > 100) ? expected : Array.Empty<string>();
+            Assert.Equal(expectedMessages, editContext.GetValidationMessages());
+        }
+    }
+
+    [Fact]
+    public void MatchesPropertyByExactName()
+    {
+        var model = new DerivedModelWithHiddenProperty { OrderID = 150 };
+        var editContext = new EditContext(model);
+        editContext.EnableDataAnnotationsValidation(_serviceProvider);
+
+        var field = new FieldIdentifier(model, "OrderID");
+        editContext.NotifyFieldChanged(field);
+        Assert.Equal(new[] { "OrderID:range" }, editContext.GetValidationMessages());
+    }
+
+    [Fact]
+    public void ValidatesInheritedPropertyFromBaseClass()
+    {
+        var model = new DerivedModelWithInheritedOnly { Description = "x" };
+        var editContext = new EditContext(model);
+        editContext.EnableDataAnnotationsValidation(_serviceProvider);
+
+        var field = new FieldIdentifier(model, nameof(DerivedModelWithInheritedOnly.BaseName));
+        editContext.NotifyFieldChanged(field);
+        Assert.Equal(new[] { "BaseName:required" }, editContext.GetValidationMessages());
+
+        model.BaseName = "ok";
+        editContext.NotifyFieldChanged(field);
+        Assert.Empty(editContext.GetValidationMessages());
+    }
+
+    [Fact]
+    public void ValidatesPropertyHiddenAtMultipleInheritanceLevels()
+    {
+        var model = new DeepDerivedModel { Tag = 150 };
+        var editContext = new EditContext(model);
+        editContext.EnableDataAnnotationsValidation(_serviceProvider);
+
+        var field = new FieldIdentifier(model, nameof(DeepDerivedModel.Tag));
+        editContext.NotifyFieldChanged(field);
+        Assert.Equal(new[] { "Tag:range" }, editContext.GetValidationMessages());
+
+        model.Tag = 5;
+        editContext.NotifyFieldChanged(field);
+        Assert.Empty(editContext.GetValidationMessages());
+    }
+
+    [Fact]
+    public void SkipsValidationWhenDerivedShadowHasNoAttributes()
+    {
+        var model = new DerivedModelWithUnattributedHiddenProperty { Name = null };
+        var editContext = new EditContext(model);
+        editContext.EnableDataAnnotationsValidation(_serviceProvider);
+
+        var field = new FieldIdentifier(model, nameof(DerivedModelWithUnattributedHiddenProperty.Name));
+        editContext.NotifyFieldChanged(field);
+        Assert.Empty(editContext.GetValidationMessages());
+    }
+
+    [Fact]
+    public void IgnoresStaticProperty()
+    {
+        var model = new ModelWithStaticProperty { Value = 0 };
+        var editContext = new EditContext(model);
+        editContext.EnableDataAnnotationsValidation(_serviceProvider);
+
+        var field = new FieldIdentifier(model, nameof(ModelWithStaticProperty.StaticValue));
+        editContext.NotifyFieldChanged(field);
+        Assert.Empty(editContext.GetValidationMessages());
+    }
+
     [Fact]
     public Task FormLevelAsyncValidationProducesMessages() => RunOnDispatcher(async () =>
     {
@@ -294,4 +398,58 @@ class TestModel
         [Required] internal string ThisWillNotBeValidatedBecauseItIsInternal { get; set; }
 #pragma warning restore 649
     }
+
+    class DerivedModelWithHiddenProperty : ModelWithHiddenBaseProperty
+    {
+        [Range(1, 100, ErrorMessage = "OrderID:range")]
+        public new int OrderID { get; set; }
+    }
+
+    class ModelWithHiddenBaseProperty
+    {
+        public object OrderID { get; set; }
+
+        public object Tag { get; set; }
+    }
+
+    class MidLevelModelWithShadow : ModelWithHiddenBaseProperty
+    {
+        public new string Tag { get; set; }
+    }
+
+    class DeepDerivedModel : MidLevelModelWithShadow
+    {
+        [Range(1, 100, ErrorMessage = "Tag:range")]
+        public new int Tag { get; set; }
+    }
+
+    class DerivedModelWithUnattributedHiddenProperty : ModelWithNamedBase
+    {
+        public new string Name { get; set; }
+    }
+
+    class ModelWithNamedBase
+    {
+        [Required(ErrorMessage = "Name:required")]
+        public object Name { get; set; }
+    }
+
+    class ModelWithStaticProperty
+    {
+        [Range(1, 100, ErrorMessage = "StaticValue:range")]
+        public static int StaticValue { get; set; }
+
+        public int Value { get; set; }
+    }
+
+    class DerivedModelWithInheritedOnly : ModelWithBaseName
+    {
+        public string Description { get; set; }
+    }
+
+    class ModelWithBaseName
+    {
+        [Required(ErrorMessage = "BaseName:required")]
+        public string BaseName { get; set; }
+    }
 }