Auto-select `type="text"` for `DateTimeOffset` values

- #6648
- a different take on #4871
- `DateTime` can also round-trip `DateTimeKind.UTC` with `[DataType("datetimeoffset")]` or `[UIHint("datetimeoffset")]`
- since they're now handled differently by default, add more `DateTime` tests
- expand tests involving `Html5DateRenderingMode.CurrentCulture`

nits: make VS-suggested changes to files updated in this PR

src/Microsoft.AspNetCore.Mvc.TagHelpers/InputTagHelper.cs

@@ -34,6 +34,7 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
                 { "Date", "date" },
                 { "DateTime", "datetime-local" },
                 { "DateTime-local", "datetime-local" },
+                { nameof(DateTimeOffset), "text" },
                 { "Time", "time" },
                 { nameof(Byte), "number" },
                 { nameof(SByte), "number" },
@@ -234,8 +235,7 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
         {
             foreach (var hint in GetInputTypeHints(modelExplorer))
             {
-                string inputType;
+                if (_defaultInputTypes.TryGetValue(hint, out var inputType))
-                if (_defaultInputTypes.TryGetValue(hint, out inputType))
                 {
                     inputTypeHint = hint;
                     return inputType;
@@ -252,8 +252,7 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
             {
                 if (modelExplorer.Model != null)
                 {
-                    bool potentialBool;
+                    if (!bool.TryParse(modelExplorer.Model.ToString(), out var potentialBool))
-                    if (!bool.TryParse(modelExplorer.Model.ToString(), out potentialBool))
                     {
                         throw new InvalidOperationException(Resources.FormatInputTagHelper_InvalidStringResult(
                             ForAttributeName,
@@ -353,8 +352,7 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
         private TagBuilder GenerateHidden(ModelExplorer modelExplorer)
         {
             var value = For.Model;
-            var byteArrayValue = value as byte[];
+            if (value is byte[] byteArrayValue)
-            if (byteArrayValue != null)
             {
                 value = Convert.ToBase64String(byteArrayValue);
             }
@@ -380,7 +378,6 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
         private string GetFormat(ModelExplorer modelExplorer, string inputTypeHint, string inputType)
         {
             string format;
-            string rfc3339Format;
             if (string.Equals("decimal", inputTypeHint, StringComparison.OrdinalIgnoreCase) &&
                 string.Equals("text", inputType, StringComparison.Ordinal) &&
                 string.IsNullOrEmpty(modelExplorer.Metadata.EditFormatString))
@@ -389,14 +386,30 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
                 // EditFormatString has precedence over this fall-back format.
                 format = "{0:0.00}";
             }
-            else if (_rfc3339Formats.TryGetValue(inputType, out rfc3339Format) &&
+            else if (ViewContext.Html5DateRenderingMode == Html5DateRenderingMode.Rfc3339 &&
-                ViewContext.Html5DateRenderingMode == Html5DateRenderingMode.Rfc3339 &&
                 !modelExplorer.Metadata.HasNonDefaultEditFormat &&
-                (typeof(DateTime) == modelExplorer.Metadata.UnderlyingOrModelType || typeof(DateTimeOffset) == modelExplorer.Metadata.UnderlyingOrModelType))
+                (typeof(DateTime) == modelExplorer.Metadata.UnderlyingOrModelType ||
+                 typeof(DateTimeOffset) == modelExplorer.Metadata.UnderlyingOrModelType))
             {
-                // Rfc3339 mode _may_ override EditFormatString in a limited number of cases e.g. EditFormatString
+                // Rfc3339 mode _may_ override EditFormatString in a limited number of cases. Happens only when
-                // must be a default format (i.e. came from a built-in [DataType] attribute).
+                // EditFormatString has a default format i.e. came from a [DataType] attribute.
-                format = rfc3339Format;
+                if (string.Equals("text", inputType) &&
+                    string.Equals(nameof(DateTimeOffset), inputTypeHint, StringComparison.OrdinalIgnoreCase))
+                {
+                    // Auto-select a format that round-trips Offset and sub-Second values in a DateTimeOffset. Not
+                    // done if user chose the "text" type in .cshtml file or with data annotations i.e. when
+                    // inputTypeHint==null or "text".
+                    format = _rfc3339Formats["datetime"];
+                }
+                else if (_rfc3339Formats.TryGetValue(inputType, out var rfc3339Format))
+                {
+                    format = rfc3339Format;
+                }
+                else
+                {
+                    // Otherwise use default EditFormatString.
+                    format = modelExplorer.Metadata.EditFormatString;
+                }
             }
             else
             {
@@ -428,7 +441,7 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
                 fieldType = modelExplorer.Metadata.UnderlyingOrModelType;
             }
 
-            foreach (string typeName in TemplateRenderer.GetTypeNames(modelExplorer.Metadata, fieldType))
+            foreach (var typeName in TemplateRenderer.GetTypeNames(modelExplorer.Metadata, fieldType))
             {
                 yield return typeName;
             }

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

@@ -197,8 +197,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
         {
             var htmlAttributes = HtmlHelper.AnonymousObjectToHtmlAttributes(htmlAttributesObject);
 
-            object htmlClassObject;
+            if (htmlAttributes.TryGetValue("class", out var htmlClassObject))
-            if (htmlAttributes.TryGetValue("class", out htmlClassObject))
             {
                 var htmlClassName = htmlClassObject + " " + className;
                 htmlAttributes["class"] = htmlClassName;
@@ -347,10 +346,10 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
             return GenerateTextBox(htmlHelper, inputType: "email");
         }
 
-        public static IHtmlContent DateTimeInputTemplate(IHtmlHelper htmlHelper)
+        public static IHtmlContent DateTimeOffsetTemplate(IHtmlHelper htmlHelper)
         {
             ApplyRfc3339DateFormattingIfNeeded(htmlHelper, "{0:yyyy-MM-ddTHH:mm:ss.fffK}");
-            return GenerateTextBox(htmlHelper, inputType: "datetime");
+            return GenerateTextBox(htmlHelper, inputType: "text");
         }
 
         public static IHtmlContent DateTimeLocalInputTemplate(IHtmlHelper htmlHelper)

src/Microsoft.AspNetCore.Mvc.ViewFeatures/ViewFeatures/TemplateRenderer.cs

@@ -50,6 +50,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
                 { "Date", DefaultEditorTemplates.DateInputTemplate },
                 { "DateTime", DefaultEditorTemplates.DateTimeLocalInputTemplate },
                 { "DateTime-local", DefaultEditorTemplates.DateTimeLocalInputTemplate },
+                { nameof(DateTimeOffset), DefaultEditorTemplates.DateTimeOffsetTemplate },
                 { "Time", DefaultEditorTemplates.TimeInputTemplate },
                 { typeof(byte).Name, DefaultEditorTemplates.NumberInputTemplate },
                 { typeof(sbyte).Name, DefaultEditorTemplates.NumberInputTemplate },
@@ -115,7 +116,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
             var defaultActions = GetDefaultActions();
             var modeViewPath = _readOnly ? DisplayTemplateViewPath : EditorTemplateViewPath;
 
-            foreach (string viewName in GetViewNames())
+            foreach (var viewName in GetViewNames())
             {
                 var viewEngineResult = _viewEngine.GetView(_viewContext.ExecutingFilePath, viewName, isMainPage: false);
                 if (!viewEngineResult.Success)
@@ -141,8 +142,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
                     }
                 }
 
-                Func<IHtmlHelper, IHtmlContent> defaultAction;
+                if (defaultActions.TryGetValue(viewName, out var defaultAction))
-                if (defaultActions.TryGetValue(viewName, out defaultAction))
                 {
                     return defaultAction(MakeHtmlHelper(_viewContext, _viewData));
                 }
@@ -255,8 +255,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
         {
             var newHelper = viewContext.HttpContext.RequestServices.GetRequiredService<IHtmlHelper>();
 
-            var contextable = newHelper as IViewContextAware;
+            if (newHelper is IViewContextAware contextable)
-            if (contextable != null)
             {
                 var newViewContext = new ViewContext(viewContext, viewContext.View, viewData, viewContext.Writer);
                 contextable.Contextualize(newViewContext);

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

@@ -28,7 +28,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
 <validationMessageElement class=""field-validation-error"">An error occurred.</validationMessageElement>
 <input id=""Prefix!Property1"" name=""Prefix.Property1"" type=""text"" value="""" />
 <div class=""editor-label""><label for=""MyDate"">MyDate</label></div>
-<div class=""editor-field""><input class=""text-box single-line"" id=""MyDate"" name=""MyDate"" type=""datetime-local"" value=""2000-01-02T03:04:05.060"" /> </div>
+<div class=""editor-field""><input class=""text-box single-line"" id=""MyDate"" name=""MyDate"" type=""text"" value=""2000-01-02T03:04:05.060&#x2B;00:00"" /> </div>
 
 <div class=""validation-summary-errors""><validationSummaryElement>MySummary</validationSummaryElement>
 <ul><li>A model error occurred.</li>
@@ -36,7 +36,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
 <validationMessageElement class=""field-validation-error"">An error occurred.</validationMessageElement>
 <input id=""Prefix!Property1"" name=""Prefix.Property1"" type=""text"" value="""" />
 <div class=""editor-label""><label for=""MyDate"">MyDate</label></div>
-<div class=""editor-field""><input class=""text-box single-line"" id=""MyDate"" name=""MyDate"" type=""datetime-local"" value=""2000-01-02T03:04:05.060"" /> </div>
+<div class=""editor-field""><input class=""text-box single-line"" id=""MyDate"" name=""MyDate"" type=""text"" value=""2000-01-02T03:04:05.060&#x2B;00:00"" /> </div>
 
 False";
 
@@ -59,7 +59,7 @@ False";
 <ValidationInView class=""field-validation-error"" data-valmsg-for=""Error"" data-valmsg-replace=""true"">An error occurred.</ValidationInView>
 <input id=""Prefix!Property1"" name=""Prefix.Property1"" type=""text"" value="""" />
 <div class=""editor-label""><label for=""MyDate"">MyDate</label></div>
-<div class=""editor-field""><input class=""text-box single-line"" data-val=""true"" data-val-required=""The MyDate field is required."" id=""MyDate"" name=""MyDate"" type=""datetime-local"" value=""02/01/2000 03:04:05 &#x2B;00:00"" /> <ValidationInView class=""field-validation-valid"" data-valmsg-for=""MyDate"" data-valmsg-replace=""true""></ValidationInView></div>
+<div class=""editor-field""><input class=""text-box single-line"" data-val=""true"" data-val-required=""The MyDate field is required."" id=""MyDate"" name=""MyDate"" type=""text"" value=""02/01/2000 03:04:05 &#x2B;00:00"" /> <ValidationInView class=""field-validation-valid"" data-valmsg-for=""MyDate"" data-valmsg-replace=""true""></ValidationInView></div>
 
 True
 <div class=""validation-summary-errors""><ValidationSummaryInPartialView>MySummary</ValidationSummaryInPartialView>
@@ -68,7 +68,7 @@ True
 <ValidationInPartialView class=""field-validation-error"" data-valmsg-for=""Error"" data-valmsg-replace=""true"">An error occurred.</ValidationInPartialView>
 <input id=""Prefix!Property1"" name=""Prefix.Property1"" type=""text"" value="""" />
 <div class=""editor-label""><label for=""MyDate"">MyDate</label></div>
-<div class=""editor-field""><input class=""text-box single-line"" id=""MyDate"" name=""MyDate"" type=""datetime-local"" value=""02/01/2000 03:04:05 &#x2B;00:00"" /> <ValidationInPartialView class=""field-validation-valid"" data-valmsg-for=""MyDate"" data-valmsg-replace=""true""></ValidationInPartialView></div>
+<div class=""editor-field""><input class=""text-box single-line"" id=""MyDate"" name=""MyDate"" type=""text"" value=""02/01/2000 03:04:05 &#x2B;00:00"" /> <ValidationInPartialView class=""field-validation-valid"" data-valmsg-for=""MyDate"" data-valmsg-replace=""true""></ValidationInPartialView></div>
 
 True";
 

test/Microsoft.AspNetCore.Mvc.TagHelpers.Test/InputTagHelperTest.cs

@@ -388,7 +388,7 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
 
         [Theory]
         [InlineData("datetime", "datetime")]
-        [InlineData(null, "datetime-local")]
+        [InlineData(null, "text")]
         [InlineData("hidden", "hidden")]
         public void Process_GeneratesFormattedOutput(string specifiedType, string expectedType)
         {
@@ -457,6 +457,77 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
             Assert.Equal(expectedTagName, output.TagName);
         }
 
+        [Theory]
+        [InlineData("datetime", "datetime")]
+        [InlineData(null, "datetime-local")]
+        [InlineData("hidden", "hidden")]
+        public void Process_GeneratesFormattedOutput_ForDateTime(string specifiedType, string expectedType)
+        {
+            // Arrange
+            var expectedAttributes = new TagHelperAttributeList
+            {
+                { "type", expectedType },
+                { "id", nameof(Model.DateTime) },
+                { "name", nameof(Model.DateTime) },
+                { "valid", "from validation attributes" },
+                { "value", "datetime: 2011-08-31T05:30:45.0000000Z" },
+            };
+            var expectedTagName = "not-input";
+            var container = new Model
+            {
+                DateTime = new DateTime(2011, 8, 31, hour: 5, minute: 30, second: 45, kind: DateTimeKind.Utc),
+            };
+
+            var allAttributes = new TagHelperAttributeList
+            {
+                { "type", specifiedType },
+            };
+            var context = new TagHelperContext(
+                tagName: "input",
+                allAttributes: allAttributes,
+                items: new Dictionary<object, object>(),
+                uniqueId: "test");
+            var output = new TagHelperOutput(
+                expectedTagName,
+                new TagHelperAttributeList(),
+                getChildContentAsync: (useCachedResult, encoder) =>
+                {
+                    throw new Exception("getChildContentAsync should not be called.");
+                })
+            {
+                TagMode = TagMode.StartTagOnly,
+            };
+
+            var htmlGenerator = new TestableHtmlGenerator(new EmptyModelMetadataProvider())
+            {
+                ValidationAttributes =
+                {
+                    {  "valid", "from validation attributes" },
+                }
+            };
+
+            var tagHelper = GetTagHelper(
+                htmlGenerator,
+                container,
+                typeof(Model),
+                model: container.DateTime,
+                propertyName: nameof(Model.DateTime),
+                expressionName: nameof(Model.DateTime));
+            tagHelper.Format = "datetime: {0:o}";
+            tagHelper.InputTypeName = specifiedType;
+
+            // Act
+            tagHelper.Process(context, output);
+
+            // Assert
+            Assert.Equal(expectedAttributes, output.Attributes);
+            Assert.Empty(output.PreContent.GetContent());
+            Assert.Empty(output.Content.GetContent());
+            Assert.Empty(output.PostContent.GetContent());
+            Assert.Equal(TagMode.StartTagOnly, output.TagMode);
+            Assert.Equal(expectedTagName, output.TagName);
+        }
+
         [Fact]
         public async Task ProcessAsync_CallsGenerateCheckBox_WithExpectedParameters()
         {
@@ -966,6 +1037,7 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
                     { "datetime", null, "datetime-local" },
                     { "datetime-local", null, "datetime-local" },
                     { "DATETIME-local", null, "datetime-local" },
+                    { "datetimeOffset", null, "text" },
                     { "Decimal", "{0:0.00}", "text" },
                     { "Double", null, "text" },
                     { "Int16", null, "number" },
@@ -1139,15 +1211,15 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
         [InlineData("Date", Html5DateRenderingMode.Rfc3339, "{0:yyyy-MM-dd}", "date")]
         [InlineData("DateTime", Html5DateRenderingMode.CurrentCulture, null, "datetime-local")]
         [InlineData("DateTime", Html5DateRenderingMode.Rfc3339, "{0:yyyy-MM-ddTHH:mm:ss.fff}", "datetime-local")]
-        [InlineData("DateTimeOffset", Html5DateRenderingMode.CurrentCulture, null, "datetime-local")]
+        [InlineData("DateTimeOffset", Html5DateRenderingMode.CurrentCulture, null, "text")]
-        [InlineData("DateTimeOffset", Html5DateRenderingMode.Rfc3339, "{0:yyyy-MM-ddTHH:mm:ss.fff}", "datetime-local")]
+        [InlineData("DateTimeOffset", Html5DateRenderingMode.Rfc3339, "{0:yyyy-MM-ddTHH:mm:ss.fffK}", "text")]
         [InlineData("DateTimeLocal", Html5DateRenderingMode.CurrentCulture, null, "datetime-local")]
         [InlineData("DateTimeLocal", Html5DateRenderingMode.Rfc3339, "{0:yyyy-MM-ddTHH:mm:ss.fff}", "datetime-local")]
         [InlineData("Time", Html5DateRenderingMode.CurrentCulture, "{0:t}", "time")]    // Format from [DataType].
         [InlineData("Time", Html5DateRenderingMode.Rfc3339, "{0:HH:mm:ss.fff}", "time")]
         [InlineData("NullableDate", Html5DateRenderingMode.Rfc3339, "{0:yyyy-MM-dd}", "date")]
         [InlineData("NullableDateTime", Html5DateRenderingMode.Rfc3339, "{0:yyyy-MM-ddTHH:mm:ss.fff}", "datetime-local")]
-        [InlineData("NullableDateTimeOffset", Html5DateRenderingMode.Rfc3339, "{0:yyyy-MM-ddTHH:mm:ss.fff}", "datetime-local")]
+        [InlineData("NullableDateTimeOffset", Html5DateRenderingMode.Rfc3339, "{0:yyyy-MM-ddTHH:mm:ss.fffK}", "text")]
         public async Task ProcessAsync_CallsGenerateTextBox_AddsExpectedAttributesForRfc3339(
             string propertyName,
             Html5DateRenderingMode dateRenderingMode,

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

@@ -16,6 +16,7 @@ using Microsoft.AspNetCore.Mvc.ModelBinding;
 using Microsoft.AspNetCore.Mvc.Rendering;
 using Microsoft.AspNetCore.Mvc.TestCommon;
 using Microsoft.AspNetCore.Mvc.ViewEngines;
+using Microsoft.AspNetCore.Testing;
 using Moq;
 using Xunit;
 
@@ -52,6 +53,8 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
                     { "datetime", "__TextBox__ class='text-box single-line' type='datetime-local'" },
                     { "DateTime-local", "__TextBox__ class='text-box single-line' type='datetime-local'" },
                     { "DATETIME-LOCAL", "__TextBox__ class='text-box single-line' type='datetime-local'" },
+                    { "datetimeoffset", "__TextBox__ class='text-box single-line' type='text'" },
+                    { "DateTimeOffset", "__TextBox__ class='text-box single-line' type='text'" },
                     { "Time", "__TextBox__ class='text-box single-line' type='time'" },
                     { "time", "__TextBox__ class='text-box single-line' type='time'" },
                     { "Byte", "__TextBox__ class='text-box single-line' type='number'" },
@@ -776,7 +779,7 @@ Environment.NewLine;
             var requiredMessage = ValidationAttributeUtil.GetRequiredErrorMessage("DateTimeOffset");
             var expectedInput = "<input class=\"HtmlEncode[[text-box single-line]]\" data-val=\"HtmlEncode[[true]]\" " +
                 $"data-val-required=\"HtmlEncode[[{requiredMessage}]]\" id=\"HtmlEncode[[FieldPrefix]]\" " +
-                "name=\"HtmlEncode[[FieldPrefix]]\" type=\"HtmlEncode[[datetime]]\" value=\"HtmlEncode[[2000-01-02T03:04:05.006]]\" />";
+                "name=\"HtmlEncode[[FieldPrefix]]\" type=\"HtmlEncode[[datetime]]\" value=\"HtmlEncode[[2000-01-02T03:04:05.060+00:00]]\" />";
 
             var offset = TimeSpan.FromHours(0);
             var model = new DateTimeOffset(
@@ -786,7 +789,7 @@ Environment.NewLine;
                 hour: 3,
                 minute: 4,
                 second: 5,
-                millisecond: 6,
+                millisecond: 60,
                 offset: offset);
             var viewEngine = new Mock<ICompositeViewEngine>(MockBehavior.Strict);
             viewEngine
@@ -814,13 +817,19 @@ Environment.NewLine;
             Assert.Equal(expectedInput, HtmlContentUtilities.HtmlContentToString(result));
         }
 
-        // DateTime-local is not special-cased unless using Html5DateRenderingMode.Rfc3339.
+        // Html5DateRenderingMode.Rfc3339 is enabled by default.
         [Theory]
+        [InlineData(null, null, "2000-01-02T03:04:05.060-05:00", "text")]
         [InlineData("date", "{0:d}", "2000-01-02", "date")]
-        [InlineData("datetime", null, "2000-01-02T03:04:05.006", "datetime-local")]
+        [InlineData("datetime", null, "2000-01-02T03:04:05.060", "datetime-local")]
-        [InlineData("datetime-local", null, "2000-01-02T03:04:05.006", "datetime-local")]
+        [InlineData("datetime-local", null, "2000-01-02T03:04:05.060", "datetime-local")]
-        [InlineData("time", "{0:t}", "03:04:05.006", "time")]
+        [InlineData("DateTimeOffset", "{0:o}", "2000-01-02T03:04:05.060-05:00", "text")]
-        public void Editor_FindsCorrectDateOrTimeTemplate(string dataTypeName, string editFormatString, string expectedFormat, string expectedType)
+        [InlineData("time", "{0:t}", "03:04:05.060", "time")]
+        public void Editor_FindsCorrectDateOrTimeTemplate(
+            string dataTypeName,
+            string editFormatString,
+            string expectedFormat,
+            string expectedType)
         {
             // Arrange
             var requiredMessage = ValidationAttributeUtil.GetRequiredErrorMessage("DateTimeOffset");
@@ -830,63 +839,7 @@ Environment.NewLine;
                 expectedType +
                 "]]\" value=\"HtmlEncode[[" + expectedFormat + "]]\" />";
 
-            var offset = TimeSpan.FromHours(0);
+            var offset = TimeSpan.FromHours(-5);
-            var model = new DateTimeOffset(
-                year: 2000,
-                month: 1,
-                day: 2,
-                hour: 3,
-                minute: 4,
-                second: 5,
-                millisecond: 6,
-                offset: offset);
-            var viewEngine = new Mock<ICompositeViewEngine>(MockBehavior.Strict);
-            viewEngine
-                .Setup(v => v.GetView(/*executingFilePath*/ null, It.IsAny<string>(), /*isMainPage*/ false))
-                .Returns(ViewEngineResult.NotFound(string.Empty, Enumerable.Empty<string>()));
-            viewEngine
-                .Setup(v => v.FindView(It.IsAny<ActionContext>(), It.IsAny<string>(), /*isMainPage*/ false))
-                .Returns(ViewEngineResult.NotFound(string.Empty, Enumerable.Empty<string>()));
-
-            var provider = new TestModelMetadataProvider();
-            provider.ForType<DateTimeOffset>().DisplayDetails(dd =>
-            {
-                dd.DataTypeName = dataTypeName;
-                dd.EditFormatString = editFormatString; // What [DataType] does for given type.
-            });
-
-            var helper = DefaultTemplatesUtilities.GetHtmlHelper(
-                model,
-                Mock.Of<IUrlHelper>(),
-                viewEngine.Object,
-                provider);
-            helper.ViewData.TemplateInfo.HtmlFieldPrefix = "FieldPrefix";
-
-            // Act
-            var result = helper.Editor(string.Empty);
-
-            // Assert
-            Assert.Equal(expectedInput, HtmlContentUtilities.HtmlContentToString(result));
-        }
-
-        [Theory]
-        [InlineData("date", "{0:d}", "2000-01-02", "date")]
-        [InlineData("datetime", null, "2000-01-02T03:04:05.060", "datetime-local")]
-        [InlineData("datetime-local", null, "2000-01-02T03:04:05.060", "datetime-local")]
-        [InlineData("time", "{0:t}", "03:04:05.060", "time")]
-        public void Editor_AppliesRfc3339(string dataTypeName, string editFormatString, string expectedFormat, string expectedType)
-        {
-            // Arrange
-            var requiredMessage = ValidationAttributeUtil.GetRequiredErrorMessage("DateTimeOffset");
-            var expectedInput =
-                "<input class=\"HtmlEncode[[text-box single-line]]\" data-val=\"HtmlEncode[[true]]\" " +
-                $"data-val-required=\"HtmlEncode[[{requiredMessage}]]\" id=\"HtmlEncode[[FieldPrefix]]\" " +
-                "name=\"HtmlEncode[[FieldPrefix]]\" type=\"HtmlEncode[[" +
-                expectedType +
-                "]]\" value=\"HtmlEncode[[" + expectedFormat + "]]\" />";
-
-            // Place DateTime-local value in current timezone.
-            var offset = string.Equals(string.Empty, dataTypeName) ? DateTimeOffset.Now.Offset : TimeSpan.FromHours(0);
             var model = new DateTimeOffset(
                 year: 2000,
                 month: 1,
@@ -916,7 +869,193 @@ Environment.NewLine;
                 Mock.Of<IUrlHelper>(),
                 viewEngine.Object,
                 provider);
-            helper.Html5DateRenderingMode = Html5DateRenderingMode.Rfc3339;
+            helper.ViewData.TemplateInfo.HtmlFieldPrefix = "FieldPrefix";
+
+            // Act
+            var result = helper.Editor(string.Empty);
+
+            // Assert
+            Assert.Equal(expectedInput, HtmlContentUtilities.HtmlContentToString(result));
+        }
+
+        // Html5DateRenderingMode.Rfc3339 can be disabled.
+        [Theory]
+        [InlineData(null, null, "02/01/2000 03:04:05 -05:00", "text")]
+        [InlineData("date", "{0:d}", "02/01/2000", "date")]
+        [InlineData("datetime", null, "02/01/2000 03:04:05 -05:00", "datetime-local")]
+        [InlineData("datetime-local", null, "02/01/2000 03:04:05 -05:00", "datetime-local")]
+        [InlineData("DateTimeOffset", "{0:o}", "2000-01-02T03:04:05.0600000-05:00", "text")]
+        [InlineData("time", "{0:t}", "03:04", "time")]
+        [ReplaceCulture]
+        public void Editor_FindsCorrectDateOrTimeTemplate_NotRfc3339(
+            string dataTypeName,
+            string editFormatString,
+            string expectedFormat,
+            string expectedType)
+        {
+            // Arrange
+            var requiredMessage = ValidationAttributeUtil.GetRequiredErrorMessage("DateTimeOffset");
+            var expectedInput =
+                "<input class=\"HtmlEncode[[text-box single-line]]\" data-val=\"HtmlEncode[[true]]\" " +
+                $"data-val-required=\"HtmlEncode[[{requiredMessage}]]\" id=\"HtmlEncode[[FieldPrefix]]\" " +
+                "name=\"HtmlEncode[[FieldPrefix]]\" type=\"HtmlEncode[[" +
+                expectedType +
+                "]]\" value=\"HtmlEncode[[" + expectedFormat + "]]\" />";
+
+            var offset = TimeSpan.FromHours(-5);
+            var model = new DateTimeOffset(
+                year: 2000,
+                month: 1,
+                day: 2,
+                hour: 3,
+                minute: 4,
+                second: 5,
+                millisecond: 60,
+                offset: offset);
+            var viewEngine = new Mock<ICompositeViewEngine>(MockBehavior.Strict);
+            viewEngine
+                .Setup(v => v.GetView(/*executingFilePath*/ null, It.IsAny<string>(), /*isMainPage*/ false))
+                .Returns(ViewEngineResult.NotFound(string.Empty, Enumerable.Empty<string>()));
+            viewEngine
+                .Setup(v => v.FindView(It.IsAny<ActionContext>(), It.IsAny<string>(), /*isMainPage*/ false))
+                .Returns(ViewEngineResult.NotFound(string.Empty, Enumerable.Empty<string>()));
+
+            var provider = new TestModelMetadataProvider();
+            provider.ForType<DateTimeOffset>().DisplayDetails(dd =>
+            {
+                dd.DataTypeName = dataTypeName;
+                dd.EditFormatString = editFormatString; // What [DataType] does for given type.
+            });
+
+            var helper = DefaultTemplatesUtilities.GetHtmlHelper(
+                model,
+                Mock.Of<IUrlHelper>(),
+                viewEngine.Object,
+                provider);
+            helper.Html5DateRenderingMode = Html5DateRenderingMode.CurrentCulture;
+            helper.ViewData.TemplateInfo.HtmlFieldPrefix = "FieldPrefix";
+
+            // Act
+            var result = helper.Editor(string.Empty);
+
+            // Assert
+            Assert.Equal(expectedInput, HtmlContentUtilities.HtmlContentToString(result));
+        }
+
+        // Html5DateRenderingMode.Rfc3339 is enabled by default.
+        [Theory]
+        [InlineData(null, null, "2000-01-02T03:04:05.060", "datetime-local")]
+        [InlineData("date", "{0:d}", "2000-01-02", "date")]
+        [InlineData("datetime", null, "2000-01-02T03:04:05.060", "datetime-local")]
+        [InlineData("datetime-local", null, "2000-01-02T03:04:05.060", "datetime-local")]
+        [InlineData("DateTimeOffset", "{0:o}", "2000-01-02T03:04:05.060Z", "text")]
+        [InlineData("time", "{0:t}", "03:04:05.060", "time")]
+        public void Editor_FindsCorrectDateOrTimeTemplate_ForDateTime(
+            string dataTypeName,
+            string editFormatString,
+            string expectedFormat,
+            string expectedType)
+        {
+            // Arrange
+            var requiredMessage = ValidationAttributeUtil.GetRequiredErrorMessage("DateTime");
+            var expectedInput = "<input class=\"HtmlEncode[[text-box single-line]]\" data-val=\"HtmlEncode[[true]]\" " +
+                $"data-val-required=\"HtmlEncode[[{requiredMessage}]]\" id=\"HtmlEncode[[FieldPrefix]]\" " +
+                "name=\"HtmlEncode[[FieldPrefix]]\" type=\"HtmlEncode[[" +
+                expectedType +
+                "]]\" value=\"HtmlEncode[[" + expectedFormat + "]]\" />";
+
+            var model = new DateTime(
+                year: 2000,
+                month: 1,
+                day: 2,
+                hour: 3,
+                minute: 4,
+                second: 5,
+                millisecond: 60,
+                kind: DateTimeKind.Utc);
+            var viewEngine = new Mock<ICompositeViewEngine>(MockBehavior.Strict);
+            viewEngine
+                .Setup(v => v.GetView(/*executingFilePath*/ null, It.IsAny<string>(), /*isMainPage*/ false))
+                .Returns(ViewEngineResult.NotFound(string.Empty, Enumerable.Empty<string>()));
+            viewEngine
+                .Setup(v => v.FindView(It.IsAny<ActionContext>(), It.IsAny<string>(), /*isMainPage*/ false))
+                .Returns(ViewEngineResult.NotFound(string.Empty, Enumerable.Empty<string>()));
+
+            var provider = new TestModelMetadataProvider();
+            provider.ForType<DateTime>().DisplayDetails(dd =>
+            {
+                dd.DataTypeName = dataTypeName;
+                dd.EditFormatString = editFormatString; // What [DataType] does for given type.
+            });
+
+            var helper = DefaultTemplatesUtilities.GetHtmlHelper(
+                model,
+                Mock.Of<IUrlHelper>(),
+                viewEngine.Object,
+                provider);
+            helper.ViewData.TemplateInfo.HtmlFieldPrefix = "FieldPrefix";
+
+            // Act
+            var result = helper.Editor(string.Empty);
+
+            // Assert
+            Assert.Equal(expectedInput, HtmlContentUtilities.HtmlContentToString(result));
+        }
+
+        // Html5DateRenderingMode.Rfc3339 can be disabled.
+        [Theory]
+        [InlineData(null, null, "02/01/2000 03:04:05", "datetime-local")]
+        [InlineData("date", "{0:d}", "02/01/2000", "date")]
+        [InlineData("datetime", null, "02/01/2000 03:04:05", "datetime-local")]
+        [InlineData("datetime-local", null, "02/01/2000 03:04:05", "datetime-local")]
+        [InlineData("DateTimeOffset", "{0:o}", "2000-01-02T03:04:05.0600000Z", "text")]
+        [InlineData("time", "{0:t}", "03:04", "time")]
+        [ReplaceCulture]
+        public void Editor_FindsCorrectDateOrTimeTemplate_ForDateTimeNotRfc3339(
+            string dataTypeName,
+            string editFormatString,
+            string expectedFormat,
+            string expectedType)
+        {
+            // Arrange
+            var requiredMessage = ValidationAttributeUtil.GetRequiredErrorMessage("DateTime");
+            var expectedInput =
+                "<input class=\"HtmlEncode[[text-box single-line]]\" data-val=\"HtmlEncode[[true]]\" " +
+                $"data-val-required=\"HtmlEncode[[{requiredMessage}]]\" id=\"HtmlEncode[[FieldPrefix]]\" " +
+                "name=\"HtmlEncode[[FieldPrefix]]\" type=\"HtmlEncode[[" +
+                expectedType +
+                "]]\" value=\"HtmlEncode[[" + expectedFormat + "]]\" />";
+
+            var model = new DateTime(
+                year: 2000,
+                month: 1,
+                day: 2,
+                hour: 3,
+                minute: 4,
+                second: 5,
+                millisecond: 60,
+                kind: DateTimeKind.Utc);
+            var viewEngine = new Mock<ICompositeViewEngine>(MockBehavior.Strict);
+            viewEngine
+                .Setup(v => v.GetView(/*executingFilePath*/ null, It.IsAny<string>(), /*isMainPage*/ false))
+                .Returns(ViewEngineResult.NotFound(string.Empty, Enumerable.Empty<string>()));
+            viewEngine
+                .Setup(v => v.FindView(It.IsAny<ActionContext>(), It.IsAny<string>(), /*isMainPage*/ false))
+                .Returns(ViewEngineResult.NotFound(string.Empty, Enumerable.Empty<string>()));
+
+            var provider = new TestModelMetadataProvider();
+            provider.ForType<DateTime>().DisplayDetails(dd =>
+            {
+                dd.DataTypeName = dataTypeName;
+                dd.EditFormatString = editFormatString; // What [DataType] does for given type.
+            });
+
+            var helper = DefaultTemplatesUtilities.GetHtmlHelper(
+                model,
+                Mock.Of<IUrlHelper>(),
+                viewEngine.Object,
+                provider);
+            helper.Html5DateRenderingMode = Html5DateRenderingMode.CurrentCulture;
             helper.ViewData.TemplateInfo.HtmlFieldPrefix = "FieldPrefix";
 
             // Act
@@ -927,6 +1066,8 @@ Environment.NewLine;
         }
 
         [Theory]
+        [InlineData(null, Html5DateRenderingMode.CurrentCulture, "text")]
+        [InlineData(null, Html5DateRenderingMode.Rfc3339, "text")]
         [InlineData("date", Html5DateRenderingMode.CurrentCulture, "date")]
         [InlineData("date", Html5DateRenderingMode.Rfc3339, "date")]
         [InlineData("datetime", Html5DateRenderingMode.CurrentCulture, "datetime-local")]