[Fixes #6591] TempData should support nullable types

src/Microsoft.AspNetCore.Mvc.ViewFeatures/Internal/SaveTempDataPropertyFilterBase.cs

@@ -96,7 +96,9 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
                     Resources.FormatTempDataProperties_PublicGetterSetter(property.DeclaringType.FullName, property.Name, nameof(TempDataAttribute)));
             }
 
-            if (!(property.PropertyType.GetTypeInfo().IsPrimitive || property.PropertyType == typeof(string)))
+            var propertyType = Nullable.GetUnderlyingType(property.PropertyType) ?? property.PropertyType;
+
+            if (!(propertyType.GetTypeInfo().IsPrimitive || propertyType == typeof(string)))
             {
                 throw new InvalidOperationException(
                     Resources.FormatTempDataProperties_PrimitiveTypeOrString(property.DeclaringType.FullName, property.Name, nameof(TempDataAttribute)));

src/Microsoft.AspNetCore.Mvc.ViewFeatures/Properties/Resources.Designer.cs

@@ -795,7 +795,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
             => string.Format(CultureInfo.CurrentCulture, GetString("ViewEnginesAreRequired"), p0, p1, p2);
 
         /// <summary>
-        /// The '{0}.{1}' property with {2} is invalid. A property using {2} must be of primitive or string type.
+        /// The '{0}.{1}' property with {2} is invalid. A property using {2} must be a primitive or string type.
         /// </summary>
         internal static string TempDataProperties_PrimitiveTypeOrString
         {
@@ -803,7 +803,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
         }
 
         /// <summary>
-        /// The '{0}.{1}' property with {2} is invalid. A property using {2} must be of primitive or string type.
+        /// The '{0}.{1}' property with {2} is invalid. A property using {2} must be a primitive or string type.
         /// </summary>
         internal static string FormatTempDataProperties_PrimitiveTypeOrString(object p0, object p1, object p2)
             => string.Format(CultureInfo.CurrentCulture, GetString("TempDataProperties_PrimitiveTypeOrString"), p0, p1, p2);

src/Microsoft.AspNetCore.Mvc.ViewFeatures/Resources.resx

@@ -287,7 +287,7 @@
     <value>'{0}.{1}' must not be empty. At least one '{2}' is required to locate a view for rendering.</value>
   </data>
   <data name="TempDataProperties_PrimitiveTypeOrString" xml:space="preserve">
-    <value>The '{0}.{1}' property with {2} is invalid. A property using {2} must be of primitive or string type.</value>
+    <value>The '{0}.{1}' property with {2} is invalid. A property using {2} must be a primitive or string type.</value>
   </data>
   <data name="TempDataProperties_PublicGetterSetter" xml:space="preserve">
     <value>The '{0}.{1}' property with {2} is invalid. A property using {2} must have a public getter and setter.</value>

test/Microsoft.AspNetCore.Mvc.FunctionalTests/TempDataPropertyTest.cs

@@ -25,13 +25,13 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
         public async Task TempDataPropertyAttribute_RetainsTempDataWithView()
         {
             // Arrange
-            var message = "Success (from Temp Data)";
+            var tempDataContent = "Success (from Temp Data)100";
             var nameValueCollection = new List<KeyValuePair<string, string>>
             {
                 new KeyValuePair<string, string>("FullName", "Bob"),
                 new KeyValuePair<string, string>("id", "1"),
             };
-            var expected = $"{message} for person {nameValueCollection[0].Value} with id {nameValueCollection[1].Value}.";
+            var expected = $"{tempDataContent} for person {nameValueCollection[0].Value} with id {nameValueCollection[1].Value}.";
             var content = new FormUrlEncodedContent(nameValueCollection);
 
             // Act 1
@@ -53,13 +53,13 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
         public async Task TempDataPropertyAttribute_RetainsTempDataWithoutView()
         {
             // Arrange
-            var message = "Success (from Temp Data)";
+            var tempDataContent = "Success (from Temp Data)100";
             var nameValueCollection = new List<KeyValuePair<string, string>>
             {
                 new KeyValuePair<string, string>("FullName", "Bob"),
                 new KeyValuePair<string, string>("id", "1"),
             };
-            var expected = $"{message} for person {nameValueCollection[0].Value} with id {nameValueCollection[1].Value}.";
+            var expected = $"{tempDataContent} for person {nameValueCollection[0].Value} with id {nameValueCollection[1].Value}.";
             var content = new FormUrlEncodedContent(nameValueCollection);
 
             // Act 1
@@ -81,14 +81,14 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
         public async Task TempDataPropertyAttribute_TempDataKept()
         {
             // Arrange
-            var message = "Success (from Temp Data)";
+            var tempDataContent = "Success (from Temp Data)100";
             var nameValueCollection = new List<KeyValuePair<string, string>>
             {
                 new KeyValuePair<string, string>("FullName", "Bob"),
                 new KeyValuePair<string, string>("id", "1"),
             };
 
-            var expected = $"{message} for person {nameValueCollection[0].Value} with id {nameValueCollection[1].Value}.";
+            var expected = $"{tempDataContent} for person {nameValueCollection[0].Value} with id {nameValueCollection[1].Value}.";
             var content = new FormUrlEncodedContent(nameValueCollection);
 
             // Act 1
@@ -103,7 +103,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
             // Assert 2
             Assert.Equal(HttpStatusCode.OK, response.StatusCode);
             var body = await response.Content.ReadAsStringAsync();
-            Assert.Equal(message, body);
+            Assert.Equal(tempDataContent, body);
 
             // Act 3
             response = await Client.SendAsync(GetRequest("TempDataProperty/ReadTempData", response));
@@ -111,21 +111,21 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
             // Assert 3
             Assert.Equal(HttpStatusCode.OK, response.StatusCode);
             body = await response.Content.ReadAsStringAsync();
-            Assert.Equal(message, body);
+            Assert.Equal(tempDataContent, body);
         }
 
         [Fact]
         public async Task TempDataPropertyAttribute_TempDataNotKept()
         {
             // Arrange
-            var message = "Success (from Temp Data)";
+            var tempDataContent = "Success (from Temp Data)100";
             var nameValueCollection = new List<KeyValuePair<string, string>>
             {
                 new KeyValuePair<string, string>("FullName", "Bob"),
                 new KeyValuePair<string, string>("id", "1"),
             };
 
-            var expected = $"{message} for person {nameValueCollection[0].Value} with id {nameValueCollection[1].Value}.";
+            var expected = $"{tempDataContent} for person {nameValueCollection[0].Value} with id {nameValueCollection[1].Value}.";
             var content = new FormUrlEncodedContent(nameValueCollection);
 
             // Act 1
@@ -140,7 +140,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
             // Assert 2
             Assert.Equal(HttpStatusCode.OK, response.StatusCode);
             var body = await response.Content.ReadAsStringAsync();
-            Assert.Equal(message, body);
+            Assert.Equal(tempDataContent, body);
 
             // Act 3
             response = await Client.SendAsync(GetRequest("TempDataProperty/ReadTempData", response));

test/Microsoft.AspNetCore.Mvc.ViewFeatures.Test/Internal/TempDataApplicationModelProviderTest.cs

@@ -16,6 +16,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
     {
         [Theory]
         [InlineData(typeof(TestController_OneTempDataProperty))]
+        [InlineData(typeof(TestController_OneNullableTempDataProperty))]
         [InlineData(typeof(TestController_TwoTempDataProperties))]
         public void AddsTempDataPropertyFilter_ForTempDataAttributeProperties(Type type)
         {
@@ -71,7 +72,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
             var exception = Assert.Throws<InvalidOperationException>(() =>
                 provider.OnProvidersExecuting(context));
 
-            Assert.Equal($"The '{typeof(TestController_OneValid_OneInvalidProperty).FullName}.{nameof(TestController_OneValid_OneInvalidProperty.Test2)}' property with {nameof(TempDataAttribute)} is invalid. A property using {nameof(TempDataAttribute)} must be of primitive or string type.", exception.Message);
+            Assert.Equal($"The '{typeof(TestController_OneValid_OneInvalidProperty).FullName}.{nameof(TestController_OneValid_OneInvalidProperty.Test2)}' property with {nameof(TempDataAttribute)} is invalid. A property using {nameof(TempDataAttribute)} must be a primitive or string type.", exception.Message);
         }
 
         [Fact]
@@ -105,7 +106,32 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
             var exception = Assert.Throws<InvalidOperationException>(() =>
                 provider.OnProvidersExecuting(context));
 
-            Assert.Equal($"The '{typeof(TestController_NonPrimitiveType).FullName}.{nameof(TestController_NonPrimitiveType.Test)}' property with {nameof(TempDataAttribute)} is invalid. A property using {nameof(TempDataAttribute)} must be of primitive or string type.", exception.Message);
+            Assert.Equal($"The '{typeof(TestController_NonPrimitiveType).FullName}.{nameof(TestController_NonPrimitiveType.Test)}' property with {nameof(TempDataAttribute)} is invalid. A property using {nameof(TempDataAttribute)} must be a primitive or string type.", exception.Message);
+        }
+
+        [Fact]
+        public void ThrowsInvalidOperationException_ForNullableNonPrimitiveType()
+        {
+            // Arrange
+            var provider = new TempDataApplicationModelProvider();
+            var defaultProvider = new DefaultApplicationModelProvider(Options.Create(new MvcOptions()));
+            var controllerType = typeof(TestController_NullableNonPrimitiveTempDataProperty);
+            var context = new ApplicationModelProviderContext(new[] { controllerType.GetTypeInfo() });
+            defaultProvider.OnProvidersExecuting(context);
+
+            // Act & Assert
+            var exception = Assert.Throws<InvalidOperationException>(() =>
+                provider.OnProvidersExecuting(context));
+
+            Assert.Equal($"The '{controllerType.FullName}.{nameof(TestController_NullableNonPrimitiveTempDataProperty.DateTime)}'"
+                + $" property with {nameof(TempDataAttribute)} is invalid. A property using {nameof(TempDataAttribute)} "
+                + $"must be a primitive or string type.", exception.Message);
+        }
+
+        public class TestController_NullableNonPrimitiveTempDataProperty
+        {
+            [TempData]
+            public DateTime? DateTime { get; set; }
         }
 
         public class TestController_OneTempDataProperty
@@ -125,6 +151,14 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
             public int Test2 { get; set; }
         }
 
+        public class TestController_OneNullableTempDataProperty
+        {
+            public string Test { get; set; }
+
+            [TempData]
+            public int? Test2 { get; set; }
+        }
+
         public class TestController_OneValid_OneInvalidProperty
         {
             [TempData]

test/WebSites/BasicWebSite/Controllers/TempDataPropertyController.cs

@@ -13,10 +13,14 @@ namespace BasicWebSite.Controllers
         [TempData]
         public string Message { get; set; }
 
+        [TempData]
+        public int? NullableInt { get; set; }
+
         [HttpPost]
         public IActionResult CreateForView(Person person)
         {
             Message = "Success (from Temp Data)";
+            NullableInt = 100;
             return RedirectToAction("DetailsView", person);
         }
 
@@ -24,35 +28,38 @@ namespace BasicWebSite.Controllers
         public IActionResult Create(Person person)
         {
             Message = "Success (from Temp Data)";
+            NullableInt = 100;
             return RedirectToAction("Details", person);
         }
 
         public IActionResult DetailsView(Person person)
         {
             ViewData["Message"] = Message;
+            ViewData["NullableInt"] = NullableInt;
             return View(person);
         }
 
         public string Details(Person person)
         {
-            return $"{Message} for person {person.FullName} with id {person.id}.";
+            return $"{Message}{NullableInt} for person {person.FullName} with id {person.id}.";
         }
 
         public StatusCodeResult CreateNoRedirect(Person person)
         {
             Message = "Success (from Temp Data)";
+            NullableInt = 100;
             return new OkResult();
         }
 
         public string TempDataKept()
         {
             TempData.Keep();
-            return Message;
+            return Message + NullableInt;
         }
 
         public string ReadTempData()
         {
-            return Message;
+            return Message + NullableInt;
         }
     }
 }

test/WebSites/BasicWebSite/Views/TempDataProperty/DetailsView.cshtml

@@ -1,2 +1,2 @@
 @model BasicWebSite.Models.Person
-@ViewData["Message"] for person @Model.FullName with id @Model.id.
+@ViewData["Message"]@ViewData["NullableInt"] for person @Model.FullName with id @Model.id.