Fix #2776 - Add implicit [BindRequired] for value type properties

src/Microsoft.AspNet.Mvc.Core/ModelBinding/Metadata/BindingMetadata.cs

@@ -38,9 +38,11 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Metadata
         /// <summary>
         /// Gets or sets a value indicating whether or not the request must contain a value for the model.
         /// Will be ignored if the model metadata being created does not represent a property.
-        /// See <see cref="ModelMetadata.IsBindingRequired"/>.
+        /// See <see cref="ModelMetadata.IsBindingRequired"/>. If <c>null</c>, the value of
+        /// <see cref="ModelMetadata.IsBindingRequired"/> will be computed based on
+        /// <see cref="ModelMetadata.ModelType"/>.
         /// </summary>
-        public bool IsBindingRequired { get; set; }
+        public bool? IsBindingRequired { get; set; }
 
         /// <summary>
         /// Gets or sets a value indicating whether or not the model is read-only. Will be ignored

src/Microsoft.AspNet.Mvc.Core/ModelBinding/Metadata/DefaultModelMetadata.cs

@@ -24,6 +24,7 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Metadata
         private ReadOnlyDictionary<object, object> _additionalValues;
         private ModelMetadata _elementMetadata;
         private bool _haveCalculatedElementMetadata;
+        private bool? _isBindingRequired;
         private bool? _isReadOnly;
         private bool? _isRequired;
         private ModelPropertyCollection _properties;
@@ -334,14 +335,24 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Metadata
         {
             get
             {
-                if (MetadataKind == ModelMetadataKind.Property)
+                if (!_isBindingRequired.HasValue)
                 {
-                    return BindingMetadata.IsBindingRequired;
+                    if (MetadataKind == ModelMetadataKind.Type)
-                }
+                    {
-                else
+                        _isBindingRequired = false;
-                {
+                    }
-                    return false;
+                    else if (BindingMetadata.IsBindingRequired.HasValue)
+                    {
+                        _isBindingRequired = BindingMetadata.IsBindingRequired;
+                    }
+                    else
+                    {
+                        // Default to IsBindingRequired = true for value types.
+                        _isBindingRequired = !AllowsNullValue(ModelType);
+                    }
                 }
+
+                return _isBindingRequired.Value;
             }
         }
 
@@ -370,14 +381,14 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Metadata
             {
                 if (!_isReadOnly.HasValue)
                 {
-                    if (BindingMetadata.IsReadOnly.HasValue)
+                    if (MetadataKind == ModelMetadataKind.Type)
-                    {
-                        _isReadOnly = BindingMetadata.IsReadOnly;
-                    }
-                    else if (MetadataKind == ModelMetadataKind.Type)
                     {
                         _isReadOnly = false;
                     }
+                    else if (BindingMetadata.IsReadOnly.HasValue)
+                    {
+                        _isReadOnly = BindingMetadata.IsReadOnly;
+                    }
                     else
                     {
                         _isReadOnly = _details.PropertySetter == null;
@@ -401,6 +412,7 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Metadata
                     }
                     else
                     {
+                        // Default to IsRequired = true for value types.
                         _isRequired = !AllowsNullValue(ModelType);
                     }
                 }

src/Microsoft.AspNet.Mvc.Formatters.Xml/DataMemberRequiredBindingMetadataProvider.cs

@@ -22,7 +22,7 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Metadata
                 return;
             }
 
-            if (context.BindingMetadata.IsBindingRequired)
+            if (context.BindingMetadata.IsBindingRequired == true)
             {
                 // This value is already required, no need to look at attributes.
                 return;

test/Microsoft.AspNet.Mvc.Core.Test/ModelBinding/ArrayModelBinderTest.cs

@@ -211,11 +211,16 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Test
             bool isReadOnly = false)
         {
             var metadataProvider = new TestModelMetadataProvider();
-            metadataProvider.ForType<int[]>().BindingDetails(bd => bd.IsReadOnly = isReadOnly);
+            metadataProvider.ForProperty(
+                typeof(ModelWithIntArrayProperty),
+                nameof(ModelWithIntArrayProperty.ArrayProperty)).BindingDetails(bd => bd.IsReadOnly = isReadOnly);
 
+            var modelMetadata = metadataProvider.GetMetadataForProperty(
+                typeof(ModelWithIntArrayProperty),
+                nameof(ModelWithIntArrayProperty.ArrayProperty));
             var bindingContext = new ModelBindingContext
             {
-                ModelMetadata = metadataProvider.GetMetadataForType(typeof(int[])),
+                ModelMetadata = modelMetadata,
                 ModelName = "someName",
                 ValueProvider = valueProvider,
                 OperationBindingContext = new OperationBindingContext
@@ -245,6 +250,11 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Test
         {
             public string[] ArrayProperty { get; set; }
         }
+
+        private class ModelWithIntArrayProperty
+        {
+            public int[] ArrayProperty { get; set; }
+        }
     }
 }
 #endif

test/Microsoft.AspNet.Mvc.Core.Test/ModelBinding/Metadata/DefaultModelMetadataTest.cs

@@ -38,14 +38,15 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Metadata
             Assert.False(metadata.HasNonDefaultEditFormat);
             Assert.False(metadata.HideSurroundingHtml);
             Assert.True(metadata.HtmlEncode);
-            Assert.False(metadata.IsBindingRequired);
+            Assert.True(metadata.IsBindingAllowed);
+            Assert.False(metadata.IsBindingRequired); // Defaults to false for reference types
             Assert.False(metadata.IsComplexType);
             Assert.False(metadata.IsCollectionType);
             Assert.False(metadata.IsEnum);
             Assert.False(metadata.IsFlagsEnum);
             Assert.False(metadata.IsNullableValueType);
             Assert.False(metadata.IsReadOnly);
-            Assert.False(metadata.IsRequired);
+            Assert.False(metadata.IsRequired); // Defaults to false for reference types
             Assert.True(metadata.ShowForDisplay);
             Assert.True(metadata.ShowForEdit);
 
@@ -172,6 +173,99 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Metadata
         {
         }
 
+        [Theory]
+        [InlineData(typeof(string))]
+        [InlineData(typeof(int))]
+        public void IsBindingAllowed_ReturnsTrue_ForTypes(Type modelType)
+        {
+            // Arrange
+            var provider = new EmptyModelMetadataProvider();
+            var detailsProvider = new EmptyCompositeMetadataDetailsProvider();
+
+            var key = ModelMetadataIdentity.ForType(modelType);
+            var cache = new DefaultMetadataDetails(key, new ModelAttributes(new object[0]));
+            cache.BindingMetadata = new BindingMetadata()
+            {
+                IsBindingAllowed = false, // Will be ignored.
+            };
+
+            var metadata = new DefaultModelMetadata(provider, detailsProvider, cache);
+
+            // Act
+            var isBindingAllowed = metadata.IsBindingAllowed;
+
+            // Assert
+            Assert.True(isBindingAllowed);
+        }
+
+        [Theory]
+        [InlineData(typeof(string))]
+        [InlineData(typeof(int))]
+        public void IsBindingRequired_ReturnsFalse_ForTypes(Type modelType)
+        {
+            // Arrange
+            var provider = new EmptyModelMetadataProvider();
+            var detailsProvider = new EmptyCompositeMetadataDetailsProvider();
+
+            var key = ModelMetadataIdentity.ForType(modelType);
+            var cache = new DefaultMetadataDetails(key, new ModelAttributes(new object[0]));
+            cache.BindingMetadata = new BindingMetadata()
+            {
+                IsBindingRequired = true, // Will be ignored.
+            };
+
+            var metadata = new DefaultModelMetadata(provider, detailsProvider, cache);
+
+            // Act
+            var isBindingRequired = metadata.IsBindingRequired;
+            
+            // Assert
+            Assert.False(isBindingRequired);
+        }
+
+        [Theory]
+        [InlineData(typeof(string))]
+        [InlineData(typeof(IDisposable))]
+        [InlineData(typeof(Nullable<int>))]
+        public void IsBindingRequired_ReturnsFalse_ForNullablePropertyTypes(Type modelType)
+        {
+            // Arrange
+            var provider = new EmptyModelMetadataProvider();
+            var detailsProvider = new EmptyCompositeMetadataDetailsProvider();
+
+            var key = ModelMetadataIdentity.ForProperty(modelType, "Test", typeof(string));
+            var cache = new DefaultMetadataDetails(key, new ModelAttributes(new object[0]));
+
+            var metadata = new DefaultModelMetadata(provider, detailsProvider, cache);
+
+            // Act
+            var isBindingRequired = metadata.IsBindingRequired;
+
+            // Assert
+            Assert.False(isBindingRequired);
+        }
+
+        [Theory]
+        [InlineData(typeof(int))]
+        [InlineData(typeof(DayOfWeek))]
+        public void IsBindingRequired_ReturnsTrue_ForNonNullablePropertyTypes(Type modelType)
+        {
+            // Arrange
+            var provider = new EmptyModelMetadataProvider();
+            var detailsProvider = new EmptyCompositeMetadataDetailsProvider();
+
+            var key = ModelMetadataIdentity.ForProperty(modelType, "Test", typeof(string));
+            var cache = new DefaultMetadataDetails(key, new ModelAttributes(new object[0]));
+
+            var metadata = new DefaultModelMetadata(provider, detailsProvider, cache);
+
+            // Act
+            var isBindingRequired = metadata.IsBindingRequired;
+
+            // Assert
+            Assert.True(isBindingRequired);
+        }
+
         [Theory]
         [InlineData(typeof(string))]
         [InlineData(typeof(IDisposable))]
@@ -486,6 +580,10 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Metadata
 
             var key = ModelMetadataIdentity.ForType(typeof(int[]));
             var cache = new DefaultMetadataDetails(key, new ModelAttributes(new object[0]));
+            cache.BindingMetadata = new BindingMetadata()
+            {
+                IsReadOnly = true, // Will be ignored.
+            };
 
             var metadata = new DefaultModelMetadata(provider, detailsProvider, cache);
 

test/Microsoft.AspNet.Mvc.Core.Test/ModelBinding/MutableObjectModelBinderTest.cs

@@ -762,8 +762,7 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
             // Arrange
             var bindingContext = new ModelBindingContext
             {
-                // Any type, even an otherwise-simple POCO with an indexer property, would do here.
+                ModelMetadata = GetMetadataForType(typeof(PersonCollection)),
-                ModelMetadata = GetMetadataForType(typeof(List<Person>)),
                 OperationBindingContext = new OperationBindingContext
                 {
                     ValidatorProvider = Mock.Of<IModelValidatorProvider>(),
@@ -942,16 +941,13 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
         }
 
         [Fact]
-        [ReplaceCulture]
+        public void ProcessDto_ValueTypeProperty_WithBindingOptional_NoValueSet_NoError()
-        public void ProcessDto_MissingDataForRequiredFields_NoErrors()
         {
             // Arrange
-            var model = new ModelWithRequired();
+            var model = new BindingOptionalProperty();
             var containerMetadata = GetMetadataForType(model.GetType());
-
             var bindingContext = CreateContext(containerMetadata, model);
 
-            // Set no properties though Age (a non-Nullable struct) and City (a class) properties are required.
             var dto = new ComplexModelDto(containerMetadata, containerMetadata.Properties);
             var testableBinder = new TestableMutableObjectModelBinder();
             var modelValidationNode = new ModelValidationNode(string.Empty, containerMetadata, model);
@@ -962,53 +958,16 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
             // Assert
             var modelStateDictionary = bindingContext.ModelState;
             Assert.True(modelStateDictionary.IsValid);
-            Assert.Empty(modelStateDictionary);
         }
 
         [Fact]
-        [ReplaceCulture]
+        public void ProcessDto_NullableValueTypeProperty_NoValueSet_NoError()
-        public void ProcessDto_ValueTypeProperty_WithRequiredAttribute_SetToNull_NoError()
         {
             // Arrange
-            var model = new ModelWithRequired();
+            var model = new NullableValueTypeProperty();
             var containerMetadata = GetMetadataForType(model.GetType());
             var bindingContext = CreateContext(containerMetadata, model);
             
-            var dto = new ComplexModelDto(containerMetadata, containerMetadata.Properties);
-            var testableBinder = new TestableMutableObjectModelBinder();
-
-            // Make Age valid and City invalid.
-            var propertyMetadata = dto.PropertyMetadata.Single(p => p.PropertyName == "Age");
-            dto.Results[propertyMetadata] = new ModelBindingResult(
-                23,
-                isModelSet: true,
-                key: "theModel.Age");
-
-            propertyMetadata = dto.PropertyMetadata.Single(p => p.PropertyName == "City");
-            dto.Results[propertyMetadata] = new ModelBindingResult(
-                null,
-                isModelSet: true,
-                key: "theModel.City");
-            var modelValidationNode = new ModelValidationNode(string.Empty, containerMetadata, model);
-
-            // Act
-            testableBinder.ProcessDto(bindingContext, dto, modelValidationNode);
-
-            // Assert
-            var modelStateDictionary = bindingContext.ModelState;
-            Assert.True(modelStateDictionary.IsValid);
-            Assert.Empty(modelStateDictionary);
-        }
-
-        [Fact]
-        public void ProcessDto_PropertyWithRequiredAttribute_NoPropertiesSet_NoError()
-        {
-            // Arrange
-            var model = new Person();
-            var containerMetadata = GetMetadataForType(model.GetType());
-            var bindingContext = CreateContext(containerMetadata, model);
-
-            // Set no properties though ValueTypeRequired (a non-Nullable struct) property is required.
             var dto = new ComplexModelDto(containerMetadata, containerMetadata.Properties);
             var testableBinder = new TestableMutableObjectModelBinder();
             var modelValidationNode = new ModelValidationNode(string.Empty, containerMetadata, model);
@@ -1091,14 +1050,14 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
         }
 
         [Fact]
-        public void ProcessDto_ValueTypeProperty_NoValue_NoError()
+        public void ProcessDto_ValueTypeProperty_NoValue_Error()
         {
             // Arrange
             var model = new Person();
             var containerMetadata = GetMetadataForType(model.GetType());
 
             var bindingContext = CreateContext(containerMetadata, model);
-            var modelStateDictionary = bindingContext.ModelState;
+            var modelState = bindingContext.ModelState;
 
             var dto = new ComplexModelDto(containerMetadata, containerMetadata.Properties);
             var testableBinder = new TestableMutableObjectModelBinder();
@@ -1124,8 +1083,14 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
             testableBinder.ProcessDto(bindingContext, dto, modelValidationNode);
 
             // Assert
-            Assert.True(modelStateDictionary.IsValid);
+            Assert.False(modelState.IsValid);
-            Assert.Empty(modelStateDictionary);
+
+            var entry = modelState["theModel." + nameof(Person.ValueTypeRequiredWithDefaultValue)];
+            var error = Assert.Single(entry.Errors);
+            Assert.Equal(
+                $"A value for the '{nameof(Person.ValueTypeRequiredWithDefaultValue)}' property was not provided.",
+                error.ErrorMessage);
+            Assert.Null(error.Exception);
         }
 
         [Fact]
@@ -1763,10 +1728,23 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
         {
         }
 
+        private class BindingOptionalProperty
+        {
+            [BindingBehavior(BindingBehavior.Optional)]
+            public int ValueTypeRequired { get; set; }
+        }
+
+        private class NullableValueTypeProperty
+        {
+            [BindingBehavior(BindingBehavior.Optional)]
+            public int? NullableValueType { get; set; }
+        }
+
         private class Person
         {
             private DateTime? _dateOfDeath;
 
+            [BindingBehavior(BindingBehavior.Optional)]
             public DateTime DateOfBirth { get; set; }
 
             public DateTime? DateOfDeath
@@ -1793,6 +1771,7 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
             public string LastName { get; set; }
             public string NonUpdateableProperty { get; private set; }
 
+            [BindingBehavior(BindingBehavior.Optional)]
             [DefaultValue(typeof(decimal), "123.456")]
             public decimal PropertyWithDefaultValue { get; set; }
 
@@ -1820,17 +1799,6 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
             public string NonUpdateableProperty { get; private set; }
         }
 
-        private class ModelWithRequired
-        {
-            public string Name { get; set; }
-
-            [Required]
-            public int Age { get; set; }
-
-            [Required]
-            public string City { get; set; }
-        }
-
         private class ModelWithBindRequired
         {
             public string Name { get; set; }
@@ -1993,6 +1961,17 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
             public string Name { get; set; }
         }
 
+        private class PersonCollection
+        {
+            public Person this[int index]
+            {
+                get
+                {
+                    return null;
+                }
+            }
+        }
+
         private class CollectionContainer
         {
             public int[] ReadOnlyArray { get; } = new int[4];

test/Microsoft.AspNet.Mvc.DataAnnotations.Test/ModelMetadataProviderTest.cs

@@ -346,7 +346,7 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Metadata
             // Arrange
             var attributes = new[] { attribute };
             var provider = CreateProvider(attributes);
-            var metadata = provider.GetMetadataForType(typeof(string));
+            var metadata = provider.GetMetadataForProperty(typeof(CoolUser), nameof(CoolUser.Name));
 
             // Act
             var result = accessor(metadata);
@@ -932,6 +932,11 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Metadata
             }
         }
 
+        public class CoolUser
+        {
+            public string Name { get; set; }
+        }
+
         public class TypeBasedBinderAttribute : Attribute, IModelNameProvider
         {
             public string Name { get; set; }
@@ -1038,6 +1043,18 @@ namespace Microsoft.AspNet.Mvc.ModelBinding.Metadata
                     key,
                     new ModelAttributes(_attributes.Concat(entry.ModelAttributes.TypeAttributes).ToArray()));
             }
+
+            protected override DefaultMetadataDetails[] CreatePropertyDetails([NotNull] ModelMetadataIdentity key)
+            {
+                var entries = base.CreatePropertyDetails(key);
+                return entries.Select(e =>
+                {
+                    return new DefaultMetadataDetails(
+                        e.Key,
+                        new ModelAttributes(_attributes.Concat(e.ModelAttributes.PropertyAttributes), e.ModelAttributes.TypeAttributes));
+                })
+                .ToArray();
+            }
         }
     }
 }

test/Microsoft.AspNet.Mvc.FunctionalTests/HtmlGenerationTest.cs

@@ -196,11 +196,12 @@ namespace Microsoft.AspNet.Mvc.FunctionalTests
             var request = new HttpRequestMessage(HttpMethod.Post, "http://localhost/Customer/HtmlGeneration_Customer");
             var nameValueCollection = new List<KeyValuePair<string, string>>
             {
-                new KeyValuePair<string,string>("Number", string.Empty),
+                new KeyValuePair<string,string>("Number", "0"),
                 new KeyValuePair<string,string>("Name", string.Empty),
                 new KeyValuePair<string,string>("Email", string.Empty),
                 new KeyValuePair<string,string>("PhoneNumber", string.Empty),
-                new KeyValuePair<string,string>("Password", string.Empty)
+                new KeyValuePair<string,string>("Password", string.Empty),
+                new KeyValuePair<string, string>("Gender", "Female"),
             };
             request.Content = new FormUrlEncodedContent(nameValueCollection);
 

test/Microsoft.AspNet.Mvc.FunctionalTests/ModelBindingFromQueryTest.cs

@@ -122,8 +122,12 @@ namespace Microsoft.AspNet.Mvc.FunctionalTests
             // Assert
             var body = await response.Content.ReadAsStringAsync();
             var result = JsonConvert.DeserializeObject<Result>(body);
-            var error = Assert.Single(result.ModelStateErrors);
+
-            Assert.Equal("TestEmployees[0].EmployeeId", error);
+            Assert.Collection(
+                result.ModelStateErrors,
+                e => Assert.Equal("TestEmployees[0].EmployeeId", e),
+                e => Assert.Equal("TestEmployees[0].EmployeeTaxId", e),
+                e => Assert.Equal("TestEmployees[0].Age", e));
         }
     }
 }

test/Microsoft.AspNet.Mvc.FunctionalTests/ModelBindingTest.cs

@@ -2218,7 +2218,7 @@ namespace Microsoft.AspNet.Mvc.FunctionalTests
             // Arrange
             var server = TestHelper.CreateServer(_app, SiteName, _configureServices);
             var client = server.CreateClient();
-            var url = "http://localhost/TryUpdateModel/TryUpdateModel_ClearsModelStateEntries";
+            var url = "http://localhost/TryUpdateModel/TryUpdateModel_ClearsModelStateEntries?id=5&price=1";
 
             // Act
             var response = await client.GetAsync(url);

test/Microsoft.AspNet.Mvc.FunctionalTests/compiler/resources/HtmlGenerationWebSite.HtmlGeneration_Customer.Index.html

@@ -3,8 +3,8 @@
     <form action="/Customer/HtmlGeneration_Customer" method="post">
         <div>
             <label class="order" for="Number">Number</label>
-            <input class="form-control input-validation-error" type="number" data-val="true" data-val-range="The field Number must be between 1 and 100." data-val-range-max="100" data-val-range-min="1" data-val-required="The Number field is required." id="Number" name="Number" value="" />
+            <input class="form-control input-validation-error" type="number" data-val="true" data-val-range="The field Number must be between 1 and 100." data-val-range-max="100" data-val-range-min="1" data-val-required="The Number field is required." id="Number" name="Number" value="0" />
-            <span class="field-validation-error" data-valmsg-for="Number" data-valmsg-replace="true">The value &#x27;&#x27; is invalid.</span>
+            <span class="field-validation-error" data-valmsg-for="Number" data-valmsg-replace="true">The field Number must be between 1 and 100.</span>
         </div>
         <div>
             <label class="order" for="Name">Name</label>
@@ -27,10 +27,10 @@
         <div>
             <label class="order" for="Gender">Gender</label>
             <input type="radio" value="Male" data-val="true" data-val-required="The Gender field is required." id="Gender" name="Gender" /> Male
-            <input type="radio" value="Female" id="Gender" name="Gender" /> Female
+            <input type="radio" value="Female" checked="checked" id="Gender" name="Gender" /> Female
             <span class="field-validation-valid" data-valmsg-for="Gender" data-valmsg-replace="true"></span>
         </div>
-        <div class="order validation-summary-errors" data-valmsg-summary="true"><ul><li>The value &#x27;&#x27; is invalid.</li>
+        <div class="order validation-summary-errors" data-valmsg-summary="true"><ul><li>The field Number must be between 1 and 100.</li>
 <li>The Password field is required.</li>
 </ul></div>
         <div class="order validation-summary-errors"><ul><li style="display:none"></li>

test/Microsoft.AspNet.Mvc.IntegrationTests/BodyValidationIntegrationTests.cs

@@ -108,7 +108,7 @@ namespace Microsoft.AspNet.Mvc.IntegrationTests
         private class Person4
         {
             [FromBody]
-            [Required]
+            [BindingBehavior(BindingBehavior.Optional)]
             public int Address { get; set; }
         }
 

test/Microsoft.AspNet.Mvc.IntegrationTests/CollectionModelBinderIntegrationTest.cs

@@ -396,10 +396,14 @@ namespace Microsoft.AspNet.Mvc.IntegrationTests
             entry = Assert.Single(modelState, kvp => kvp.Key == "parameter[0].Name").Value;
             Assert.Null(entry.Value);
             Assert.Equal(ModelValidationState.Invalid, entry.ValidationState);
+            var error = Assert.Single(entry.Errors);
+            Assert.Equal("A value for the 'Name' property was not provided.", error.ErrorMessage);
 
             entry = Assert.Single(modelState, kvp => kvp.Key == "parameter[1].Name").Value;
             Assert.Null(entry.Value);
             Assert.Equal(ModelValidationState.Invalid, entry.ValidationState);
+            error = Assert.Single(entry.Errors);
+            Assert.Equal("A value for the 'Name' property was not provided.", error.ErrorMessage);
         }
 
         [Fact]
@@ -548,6 +552,7 @@ namespace Microsoft.AspNet.Mvc.IntegrationTests
 
         private class Address4
         {
+            [BindingBehavior(BindingBehavior.Optional)]
             public int Zip { get; set; }
 
             public string Street { get; set; }
@@ -606,7 +611,7 @@ namespace Microsoft.AspNet.Mvc.IntegrationTests
 
         private class Address5
         {
-            public int Zip { get; set; }
+            public int? Zip { get; set; }
 
             [StringLength(3)]
             public string Street { get; set; }

test/Microsoft.AspNet.Mvc.IntegrationTests/MutableObjectModelBinderIntegrationTest.cs

@@ -26,6 +26,7 @@ namespace Microsoft.AspNet.Mvc.IntegrationTests
 
         private class Order1
         {
+            [BindingBehavior(BindingBehavior.Optional)]
             public int ProductId { get; set; }
 
             public Person1 Customer { get; set; }
@@ -261,7 +262,7 @@ namespace Microsoft.AspNet.Mvc.IntegrationTests
 
         private class Order2
         {
-            public int ProductId { get; set; }
+            public int? ProductId { get; set; }
 
             public Person2 Customer { get; set; }
         }
@@ -435,6 +436,7 @@ namespace Microsoft.AspNet.Mvc.IntegrationTests
 
         private class Order3
         {
+            [BindingBehavior(BindingBehavior.Optional)]
             public int ProductId { get; set; }
 
             public Person3 Customer { get; set; }
@@ -578,7 +580,7 @@ namespace Microsoft.AspNet.Mvc.IntegrationTests
 
         private class Order4
         {
-            public int ProductId { get; set; }
+            public int? ProductId { get; set; }
 
             public Person4 Customer { get; set; }
         }
@@ -1341,6 +1343,7 @@ namespace Microsoft.AspNet.Mvc.IntegrationTests
         {
             public string Name { get; set; }
 
+            [BindingBehavior(BindingBehavior.Optional)]
             public KeyValuePair<string, int> ProductId { get; set; }
         }
 

test/Microsoft.AspNet.Mvc.IntegrationTests/ValidationIntegrationTests.cs

@@ -195,7 +195,7 @@ namespace Microsoft.AspNet.Mvc.IntegrationTests
 
         private class Person3
         {
-            public int Age { get; set; }
+            public int? Age { get; set; }
 
             [Required]
             public string Name { get; set; }
@@ -1018,12 +1018,12 @@ namespace Microsoft.AspNet.Mvc.IntegrationTests
 
         private class Address
         {
-            public int Street { get; set; }
+            public int? Street { get; set; }
 
             public string State { get; set; }
 
             [Range(10000, 99999)]
-            public int Zip { get; set; }
+            public int? Zip { get; set; }
 
             public Country Country { get; set; }
         }