Allow `null` or empty `fullName` in one special case

- #6662
- users can now provide a `name` or `data-valmsg-for` attribute to avoid `ArgumentException`s
  - affects `<input>`, `<select>`, `<textarea>` elements and validation message `<div>`s
- remove `fullName` check in `DefaultHtmlGenerator.GetCurrentValues(...)` entirely

The new workaround is _not_ identical to changing `ViewData.TemplateInfo.HtmlFieldPrefix`
- does not change where expression values are found in `ModelState` or `ViewData`
- likely needs to be combined with additional workarounds i.e. for advanced use only

nits:
- clean up some excessive argument naming; add a few missing argument names
- take VS suggestions in changed classes e.g. inline a few variable declarations
- clean up some test data

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

@@ -113,6 +113,15 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
         [HtmlAttributeName("type")]
         public string InputTypeName { get; set; }
 
+        /// <summary>
+        /// The name of the &lt;input&gt; element.
+        /// </summary>
+        /// <remarks>
+        /// Passed through to the generated HTML in all cases. Also used to determine whether <see cref="For"/> is
+        /// valid with an empty <see cref="ModelExpression.Name"/>.
+        /// </remarks>
+        public string Name { get; set; }
+
         /// <summary>
         /// The value of the &lt;input&gt; element.
         /// </summary>
@@ -146,6 +155,11 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
                 output.CopyHtmlAttribute("type", context);
             }
 
+            if (Name != null)
+            {
+                output.CopyHtmlAttribute(nameof(Name), context);
+            }
+
             if (Value != null)
             {
                 output.CopyHtmlAttribute(nameof(Value), context);
@@ -183,15 +197,27 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
                 output.Attributes.SetAttribute("type", inputType);
             }
 
+            // Ensure Generator does not throw due to empty "fullName" if user provided a name attribute.
+            IDictionary<string, object> htmlAttributes = null;
+            if (string.IsNullOrEmpty(For.Name) &&
+                string.IsNullOrEmpty(ViewContext.ViewData.TemplateInfo.HtmlFieldPrefix) &&
+                !string.IsNullOrEmpty(Name))
+            {
+                htmlAttributes = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase)
+                {
+                    { "name", Name },
+                };
+            }
+
             TagBuilder tagBuilder;
             switch (inputType)
             {
                 case "hidden":
-                    tagBuilder = GenerateHidden(modelExplorer);
+                    tagBuilder = GenerateHidden(modelExplorer, htmlAttributes);
                     break;
 
                 case "checkbox":
-                    tagBuilder = GenerateCheckBox(modelExplorer, output);
+                    tagBuilder = GenerateCheckBox(modelExplorer, output, htmlAttributes);
                     break;
 
                 case "password":
@@ -200,15 +226,15 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
                         modelExplorer,
                         For.Name,
                         value: null,
-                        htmlAttributes: null);
+                        htmlAttributes: htmlAttributes);
                     break;
 
                 case "radio":
-                    tagBuilder = GenerateRadio(modelExplorer);
+                    tagBuilder = GenerateRadio(modelExplorer, htmlAttributes);
                     break;
 
                 default:
-                    tagBuilder = GenerateTextBox(modelExplorer, inputTypeHint, inputType);
+                    tagBuilder = GenerateTextBox(modelExplorer, inputTypeHint, inputType, htmlAttributes);
                     break;
             }
 
@@ -248,7 +274,10 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
             return inputTypeHint;
         }
 
-        private TagBuilder GenerateCheckBox(ModelExplorer modelExplorer, TagHelperOutput output)
+        private TagBuilder GenerateCheckBox(
+            ModelExplorer modelExplorer,
+            TagHelperOutput output,
+            IDictionary<string, object> htmlAttributes)
         {
             if (modelExplorer.ModelType == typeof(string))
             {
@@ -282,6 +311,14 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
                 var renderingMode =
                     output.TagMode == TagMode.SelfClosing ? TagRenderMode.SelfClosing : TagRenderMode.StartTag;
                 hiddenForCheckboxTag.TagRenderMode = renderingMode;
+                if (!hiddenForCheckboxTag.Attributes.ContainsKey("name") &&
+                    !string.IsNullOrEmpty(Name))
+                {
+                    // The checkbox and hidden elements should have the same name attribute value. Attributes will
+                    // match if both are present because both have a generated value. Reach here in the special case
+                    // where user provided a non-empty fallback name.
+                    hiddenForCheckboxTag.MergeAttribute("name", Name);
+                }
 
                 if (ViewContext.FormContext.CanRenderAtEndOfForm)
                 {
@@ -298,10 +335,10 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
                 modelExplorer,
                 For.Name,
                 isChecked: null,
-                htmlAttributes: null);
+                htmlAttributes: htmlAttributes);
         }
 
-        private TagBuilder GenerateRadio(ModelExplorer modelExplorer)
+        private TagBuilder GenerateRadio(ModelExplorer modelExplorer, IDictionary<string, object> htmlAttributes)
         {
             // Note empty string is allowed.
             if (Value == null)
@@ -319,10 +356,14 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
                 For.Name,
                 Value,
                 isChecked: null,
-                htmlAttributes: null);
+                htmlAttributes: htmlAttributes);
         }
 
-        private TagBuilder GenerateTextBox(ModelExplorer modelExplorer, string inputTypeHint, string inputType)
+        private TagBuilder GenerateTextBox(
+            ModelExplorer modelExplorer,
+            string inputTypeHint,
+            string inputType,
+            IDictionary<string, object> htmlAttributes)
         {
             var format = Format;
             if (string.IsNullOrEmpty(format))
@@ -338,12 +379,18 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
                     format = GetFormat(modelExplorer, inputTypeHint, inputType);
                 }
             }
-            var htmlAttributes = new Dictionary<string, object>
-            {
-                { "type", inputType }
-            };
 
-            if (string.Equals(inputType, "file") && string.Equals(inputTypeHint, TemplateRenderer.IEnumerableOfIFormFileName))
+            if (htmlAttributes == null)
+            {
+                htmlAttributes = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase);
+            }
+
+            htmlAttributes["type"] = inputType;
+            if (string.Equals(inputType, "file") &&
+                string.Equals(
+                    inputTypeHint,
+                    TemplateRenderer.IEnumerableOfIFormFileName,
+                    StringComparison.OrdinalIgnoreCase))
             {
                 htmlAttributes["multiple"] = "multiple";
             }
@@ -352,14 +399,14 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
                 ViewContext,
                 modelExplorer,
                 For.Name,
-                value: modelExplorer.Model,
+                modelExplorer.Model,
-                format: format,
+                format,
-                htmlAttributes: htmlAttributes);
+                htmlAttributes);
         }
 
         // Imitate Generator.GenerateHidden() using Generator.GenerateTextBox(). This adds support for asp-format that
         // is not available in Generator.GenerateHidden().
-        private TagBuilder GenerateHidden(ModelExplorer modelExplorer)
+        private TagBuilder GenerateHidden(ModelExplorer modelExplorer, IDictionary<string, object> htmlAttributes)
         {
             var value = For.Model;
             if (value is byte[] byteArrayValue)
@@ -367,21 +414,17 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
                 value = Convert.ToBase64String(byteArrayValue);
             }
 
+            if (htmlAttributes == null)
+            {
+                htmlAttributes = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase);
+            }
+
             // In DefaultHtmlGenerator(), GenerateTextBox() calls GenerateInput() _almost_ identically to how
             // GenerateHidden() does and the main switch inside GenerateInput() handles InputType.Text and
             // InputType.Hidden identically. No behavior differences at all when a type HTML attribute already exists.
-            var htmlAttributes = new Dictionary<string, object>
+            htmlAttributes["type"] = "hidden";
-            {
-                { "type", "hidden" }
-            };
 
-            return Generator.GenerateTextBox(
+            return Generator.GenerateTextBox(ViewContext, modelExplorer, For.Name, value, Format, htmlAttributes);
-                ViewContext,
-                modelExplorer,
-                For.Name,
-                value: value,
-                format: Format,
-                htmlAttributes: htmlAttributes);
         }
 
         // Get a fall-back format based on the metadata.
@@ -462,4 +505,4 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
             }
         }
     }
-}
+}

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

@@ -57,6 +57,15 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
         [HtmlAttributeName(ItemsAttributeName)]
         public IEnumerable<SelectListItem> Items { get; set; }
 
+        /// <summary>
+        /// The name of the &lt;input&gt; element.
+        /// </summary>
+        /// <remarks>
+        /// Passed through to the generated HTML in all cases. Also used to determine whether <see cref="For"/> is
+        /// valid with an empty <see cref="ModelExpression.Name"/>.
+        /// </remarks>
+        public string Name { get; set; }
+
         /// <inheritdoc />
         public override void Init(TagHelperContext context)
         {
@@ -89,11 +98,7 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
             var realModelType = For.ModelExplorer.ModelType;
             _allowMultiple = typeof(string) != realModelType &&
                 typeof(IEnumerable).IsAssignableFrom(realModelType);
-            _currentValues = Generator.GetCurrentValues(
+            _currentValues = Generator.GetCurrentValues(ViewContext, For.ModelExplorer, For.Name, _allowMultiple);
-                ViewContext,
-                For.ModelExplorer,
-                expression: For.Name,
-                allowMultiple: _allowMultiple);
 
             // Whether or not (not being highly unlikely) we generate anything, could update contained <option/>
             // elements. Provide selected values for <option/> tag helpers.
@@ -115,6 +120,13 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
                 throw new ArgumentNullException(nameof(output));
             }
 
+            // Pass through attribute that is also a well-known HTML attribute. Must be done prior to any copying
+            // from a TagBuilder.
+            if (Name != null)
+            {
+                output.CopyHtmlAttribute(nameof(Name), context);
+            }
+
             // Ensure GenerateSelect() _never_ looks anything up in ViewData.
             var items = Items ?? Enumerable.Empty<SelectListItem>();
 
@@ -125,6 +137,18 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
                 return;
             }
 
+            // Ensure Generator does not throw due to empty "fullName" if user provided a name attribute.
+            IDictionary<string, object> htmlAttributes = null;
+            if (string.IsNullOrEmpty(For.Name) &&
+                string.IsNullOrEmpty(ViewContext.ViewData.TemplateInfo.HtmlFieldPrefix) &&
+                !string.IsNullOrEmpty(Name))
+            {
+                htmlAttributes = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase)
+                {
+                    { "name", Name },
+                };
+            }
+
             var tagBuilder = Generator.GenerateSelect(
                 ViewContext,
                 For.ModelExplorer,
@@ -133,7 +157,7 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
                 selectList: items,
                 currentValues: _currentValues,
                 allowMultiple: _allowMultiple,
-                htmlAttributes: null);
+                htmlAttributes: htmlAttributes);
 
             if (tagBuilder != null)
             {
@@ -145,4 +169,4 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
             }
         }
     }
-}
+}

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

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Collections.Generic;
 using Microsoft.AspNetCore.Mvc.Rendering;
 using Microsoft.AspNetCore.Mvc.ViewFeatures;
 using Microsoft.AspNetCore.Razor.TagHelpers;
@@ -40,6 +41,15 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
         [HtmlAttributeName(ForAttributeName)]
         public ModelExpression For { get; set; }
 
+        /// <summary>
+        /// The name of the &lt;input&gt; element.
+        /// </summary>
+        /// <remarks>
+        /// Passed through to the generated HTML in all cases. Also used to determine whether <see cref="For"/> is
+        /// valid with an empty <see cref="ModelExpression.Name"/>.
+        /// </remarks>
+        public string Name { get; set; }
+
         /// <inheritdoc />
         /// <remarks>Does nothing if <see cref="For"/> is <c>null</c>.</remarks>
         public override void Process(TagHelperContext context, TagHelperOutput output)
@@ -54,13 +64,32 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
                 throw new ArgumentNullException(nameof(output));
             }
 
+            // Pass through attribute that is also a well-known HTML attribute. Must be done prior to any copying
+            // from a TagBuilder.
+            if (Name != null)
+            {
+                output.CopyHtmlAttribute(nameof(Name), context);
+            }
+
+            // Ensure Generator does not throw due to empty "fullName" if user provided a name attribute.
+            IDictionary<string, object> htmlAttributes = null;
+            if (string.IsNullOrEmpty(For.Name) &&
+                string.IsNullOrEmpty(ViewContext.ViewData.TemplateInfo.HtmlFieldPrefix) &&
+                !string.IsNullOrEmpty(Name))
+            {
+                htmlAttributes = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase)
+                {
+                    { "name", Name },
+                };
+            }
+
             var tagBuilder = Generator.GenerateTextArea(
                 ViewContext,
                 For.ModelExplorer,
                 For.Name,
                 rows: 0,
                 columns: 0,
-                htmlAttributes: null);
+                htmlAttributes: htmlAttributes);
 
             if (tagBuilder != null)
             {

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

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Collections.Generic;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Mvc.Rendering;
 using Microsoft.AspNetCore.Mvc.ViewFeatures;
@@ -16,6 +17,7 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
     [HtmlTargetElement("span", Attributes = ValidationForAttributeName)]
     public class ValidationMessageTagHelper : TagHelper
     {
+        private const string DataValidationForAttributeName = "data-valmsg-for";
         private const string ValidationForAttributeName = "asp-validation-for";
 
         /// <summary>
@@ -36,9 +38,6 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
 
         protected IHtmlGenerator Generator { get; }
 
-        /// <summary>
-        /// Name to be validated on the current model.
-        /// </summary>
         [HtmlAttributeName(ValidationForAttributeName)]
         public ModelExpression For { get; set; }
 
@@ -58,13 +57,27 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
 
             if (For != null)
             {
+                // Ensure Generator does not throw due to empty "fullName" if user provided data-valmsg-for attribute.
+                // Assume data-valmsg-for value is non-empty if attribute is present at all. Should align with name of
+                // another tag helper e.g. an <input/> and those tag helpers bind Name.
+                IDictionary<string, object> htmlAttributes = null;
+                if (string.IsNullOrEmpty(For.Name) &&
+                    string.IsNullOrEmpty(ViewContext.ViewData.TemplateInfo.HtmlFieldPrefix) &&
+                    output.Attributes.ContainsName(DataValidationForAttributeName))
+                {
+                    htmlAttributes = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase)
+                    {
+                        { DataValidationForAttributeName, "-non-empty-value-" },
+                    };
+                }
+
                 var tagBuilder = Generator.GenerateValidationMessage(
                     ViewContext,
                     For.ModelExplorer,
                     For.Name,
                     message: null,
                     tag: null,
-                    htmlAttributes: null);
+                    htmlAttributes: htmlAttributes);
 
                 if (tagBuilder != null)
                 {

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

@@ -214,8 +214,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
 
                 if (modelExplorer.Model != null)
                 {
-                    bool modelChecked;
+                    if (bool.TryParse(modelExplorer.Model.ToString(), out var modelChecked))
-                    if (bool.TryParse(modelExplorer.Model.ToString(), out modelChecked))
                     {
                         isChecked = modelChecked;
                     }
@@ -261,7 +260,10 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
             tagBuilder.TagRenderMode = TagRenderMode.SelfClosing;
 
             var fullName = NameAndIdProvider.GetFullHtmlFieldName(viewContext, expression);
-            tagBuilder.MergeAttribute("name", fullName);
+            if (!string.IsNullOrEmpty(fullName))
+            {
+                tagBuilder.MergeAttribute("name", fullName);
+            }
 
             return tagBuilder;
         }
@@ -363,8 +365,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
             }
 
             // Special-case opaque values and arbitrary binary data.
-            var byteArrayValue = value as byte[];
+            if (value is byte[] byteArrayValue)
-            if (byteArrayValue != null)
             {
                 value = Convert.ToBase64String(byteArrayValue);
             }
@@ -596,7 +597,8 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
             }
 
             var fullName = NameAndIdProvider.GetFullHtmlFieldName(viewContext, expression);
-            if (string.IsNullOrEmpty(fullName))
+            var htmlAttributeDictionary = GetHtmlAttributeDictionaryOrNull(htmlAttributes);
+            if (!IsFullNameValid(fullName, htmlAttributeDictionary))
             {
                 throw new ArgumentException(
                     Resources.FormatHtmlGenerator_FieldNameCannotBeNullOrEmpty(
@@ -622,17 +624,20 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
 
             var tagBuilder = new TagBuilder("select");
             tagBuilder.InnerHtml.SetHtmlContent(listItemBuilder);
-            tagBuilder.MergeAttributes(GetHtmlAttributeDictionaryOrNull(htmlAttributes));
+            tagBuilder.MergeAttributes(htmlAttributeDictionary);
-            tagBuilder.MergeAttribute("name", fullName, true /* replaceExisting */);
             NameAndIdProvider.GenerateId(viewContext, tagBuilder, fullName, IdAttributeDotReplacement);
+            if (!string.IsNullOrEmpty(fullName))
+            {
+                tagBuilder.MergeAttribute("name", fullName, replaceExisting: true);
+            }
+
             if (allowMultiple)
             {
                 tagBuilder.MergeAttribute("multiple", "multiple");
             }
 
             // If there are any errors for a named field, we add the css attribute.
-            ModelStateEntry entry;
+            if (viewContext.ViewData.ModelState.TryGetValue(fullName, out var entry))
-            if (viewContext.ViewData.ModelState.TryGetValue(fullName, out entry))
             {
                 if (entry.Errors.Count > 0)
                 {
@@ -672,7 +677,8 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
             }
 
             var fullName = NameAndIdProvider.GetFullHtmlFieldName(viewContext, expression);
-            if (string.IsNullOrEmpty(fullName))
+            var htmlAttributeDictionary = GetHtmlAttributeDictionaryOrNull(htmlAttributes);
+            if (!IsFullNameValid(fullName, htmlAttributeDictionary))
             {
                 throw new ArgumentException(
                     Resources.FormatHtmlGenerator_FieldNameCannotBeNullOrEmpty(
@@ -684,8 +690,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
                     nameof(expression));
             }
 
-            ModelStateEntry entry;
+            viewContext.ViewData.ModelState.TryGetValue(fullName, out var entry);
-            viewContext.ViewData.ModelState.TryGetValue(fullName, out entry);
 
             var value = string.Empty;
             if (entry != null && entry.AttemptedValue != null)
@@ -699,18 +704,24 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
 
             var tagBuilder = new TagBuilder("textarea");
             NameAndIdProvider.GenerateId(viewContext, tagBuilder, fullName, IdAttributeDotReplacement);
-            tagBuilder.MergeAttributes(GetHtmlAttributeDictionaryOrNull(htmlAttributes), true);
+            tagBuilder.MergeAttributes(htmlAttributeDictionary, replaceExisting: true);
             if (rows > 0)
             {
-                tagBuilder.MergeAttribute("rows", rows.ToString(CultureInfo.InvariantCulture), true);
+                tagBuilder.MergeAttribute("rows", rows.ToString(CultureInfo.InvariantCulture), replaceExisting: true);
             }
 
             if (columns > 0)
             {
-                tagBuilder.MergeAttribute("cols", columns.ToString(CultureInfo.InvariantCulture), true);
+                tagBuilder.MergeAttribute(
+                    "cols",
+                    columns.ToString(CultureInfo.InvariantCulture),
+                    replaceExisting: true);
             }
 
-            tagBuilder.MergeAttribute("name", fullName, true);
+            if (!string.IsNullOrEmpty(fullName))
+            {
+                tagBuilder.MergeAttribute("name", fullName, replaceExisting: true);
+            }
 
             AddPlaceholderAttribute(viewContext.ViewData, tagBuilder, modelExplorer, expression);
             AddValidationAttributes(viewContext, tagBuilder, modelExplorer, expression);
@@ -773,7 +784,8 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
             }
 
             var fullName = NameAndIdProvider.GetFullHtmlFieldName(viewContext, expression);
-            if (string.IsNullOrEmpty(fullName))
+            var htmlAttributeDictionary = GetHtmlAttributeDictionaryOrNull(htmlAttributes);
+            if (!IsFullNameValid(fullName, htmlAttributeDictionary, fallbackAttributeName: "data-valmsg-for"))
             {
                 throw new ArgumentException(
                     Resources.FormatHtmlGenerator_FieldNameCannotBeNullOrEmpty(
@@ -791,8 +803,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
                 return null;
             }
 
-            ModelStateEntry entry;
+            var tryGetModelStateResult = viewContext.ViewData.ModelState.TryGetValue(fullName, out var entry);
-            var tryGetModelStateResult = viewContext.ViewData.ModelState.TryGetValue(fullName, out entry);
             var modelErrors = tryGetModelStateResult ? entry.Errors : null;
 
             ModelError modelError = null;
@@ -812,8 +823,9 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
             {
                 tag = viewContext.ValidationMessageElement;
             }
+
             var tagBuilder = new TagBuilder(tag);
-            tagBuilder.MergeAttributes(GetHtmlAttributeDictionaryOrNull(htmlAttributes));
+            tagBuilder.MergeAttributes(htmlAttributeDictionary);
 
             // Only the style of the span is changed according to the errors if message is null or empty.
             // Otherwise the content and style is handled by the client-side validation.
@@ -838,7 +850,10 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
 
             if (formContext != null)
             {
-                tagBuilder.MergeAttribute("data-valmsg-for", fullName);
+                if (!string.IsNullOrEmpty(fullName))
+                {
+                    tagBuilder.MergeAttribute("data-valmsg-for", fullName);
+                }
 
                 var replaceValidationMessageContents = string.IsNullOrEmpty(message);
                 tagBuilder.MergeAttribute("data-valmsg-replace",
@@ -868,9 +883,8 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
                 return null;
             }
 
-            ModelStateEntry entryForModel;
             if (excludePropertyErrors &&
-                (!viewData.ModelState.TryGetValue(viewData.TemplateInfo.HtmlFieldPrefix, out entryForModel) ||
+                (!viewData.ModelState.TryGetValue(viewData.TemplateInfo.HtmlFieldPrefix, out var entryForModel) ||
                  entryForModel.Errors.Count == 0))
             {
                 // Client-side validation (if enabled) will not affect the generated element and element will be empty.
@@ -964,18 +978,6 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
             }
 
             var fullName = NameAndIdProvider.GetFullHtmlFieldName(viewContext, expression);
-            if (string.IsNullOrEmpty(fullName))
-            {
-                throw new ArgumentException(
-                    Resources.FormatHtmlGenerator_FieldNameCannotBeNullOrEmpty(
-                        typeof(IHtmlHelper).FullName,
-                        nameof(IHtmlHelper.Editor),
-                        typeof(IHtmlHelper<>).FullName,
-                        nameof(IHtmlHelper<object>.EditorFor),
-                        "htmlFieldName"),
-                    nameof(expression));
-            }
-
             var type = allowMultiple ? typeof(string[]) : typeof(string);
             var rawValue = GetModelStateValue(viewContext, fullName, type);
 
@@ -1133,8 +1135,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
 
         internal static object GetModelStateValue(ViewContext viewContext, string key, Type destinationType)
         {
-            ModelStateEntry entry;
+            if (viewContext.ViewData.ModelState.TryGetValue(key, out var entry) && entry.RawValue != null)
-            if (viewContext.ViewData.ModelState.TryGetValue(key, out entry) && entry.RawValue != null)
             {
                 return ModelBindingHelper.ConvertTo(entry.RawValue, destinationType, culture: null);
             }
@@ -1207,7 +1208,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
             // elements. But we support the *ForModel() methods in any lower-level template, once HtmlFieldPrefix is
             // non-empty.
             var fullName = NameAndIdProvider.GetFullHtmlFieldName(viewContext, expression);
-            if (string.IsNullOrEmpty(fullName))
+            if (!IsFullNameValid(fullName, htmlAttributes))
             {
                 throw new ArgumentException(
                     Resources.FormatHtmlGenerator_FieldNameCannotBeNullOrEmpty(
@@ -1220,11 +1221,17 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
             }
 
             var inputTypeString = GetInputTypeString(inputType);
-            var tagBuilder = new TagBuilder("input");
+            var tagBuilder = new TagBuilder("input")
-            tagBuilder.TagRenderMode = TagRenderMode.SelfClosing;
+            {
+                TagRenderMode = TagRenderMode.SelfClosing,
+            };
+
             tagBuilder.MergeAttributes(htmlAttributes);
             tagBuilder.MergeAttribute("type", inputTypeString);
-            tagBuilder.MergeAttribute("name", fullName, replaceExisting: true);
+            if (!string.IsNullOrEmpty(fullName))
+            {
+                tagBuilder.MergeAttribute("name", fullName, replaceExisting: true);
+            }
 
             var suppliedTypeString = tagBuilder.Attributes["type"];
             if (_placeholderInputTypes.Contains(suppliedTypeString))
@@ -1249,8 +1256,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
                 case InputType.Radio:
                     if (!usedModelState)
                     {
-                        var modelStateValue = GetModelStateValue(viewContext, fullName, typeof(string)) as string;
+                        if (GetModelStateValue(viewContext, fullName, typeof(string)) is string modelStateValue)
-                        if (modelStateValue != null)
                         {
                             isChecked = string.Equals(modelStateValue, valueParameter, StringComparison.Ordinal);
                             usedModelState = true;
@@ -1313,8 +1319,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
             }
 
             // If there are any errors for a named field, we add the CSS attribute.
-            ModelStateEntry entry;
+            if (viewContext.ViewData.ModelState.TryGetValue(fullName, out var entry) && entry.Errors.Count > 0)
-            if (viewContext.ViewData.ModelState.TryGetValue(fullName, out entry) && entry.Errors.Count > 0)
             {
                 tagBuilder.AddCssClass(HtmlHelper.ValidationInputCssClassName);
             }
@@ -1410,8 +1415,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
 
         private static object ConvertEnumFromString<TEnum>(string value) where TEnum : struct
         {
-            TEnum enumValue;
+            if (Enum.TryParse(value, out TEnum enumValue))
-            if (Enum.TryParse(value, out enumValue))
             {
                 return enumValue;
             }
@@ -1500,10 +1504,41 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
             return selectList;
         }
 
+        private static bool IsFullNameValid(string fullName, IDictionary<string, object> htmlAttributeDictionary)
+        {
+            return IsFullNameValid(fullName, htmlAttributeDictionary, fallbackAttributeName: "name");
+        }
+
+        private static bool IsFullNameValid(
+            string fullName,
+            IDictionary<string, object> htmlAttributeDictionary,
+            string fallbackAttributeName)
+        {
+            if (string.IsNullOrEmpty(fullName))
+            {
+                // fullName==null is normally an error because name="" is not valid in HTML 5.
+                if (htmlAttributeDictionary == null)
+                {
+                    return false;
+                }
+
+                // Check if user has provided an explicit name attribute.
+                // Generalized a bit because other attributes e.g. data-valmsg-for refer to element names.
+                htmlAttributeDictionary.TryGetValue(fallbackAttributeName, out var attributeObject);
+                var attributeString = Convert.ToString(attributeObject, CultureInfo.InvariantCulture);
+                if (string.IsNullOrEmpty(attributeString))
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+
         /// <inheritdoc />
         public IHtmlContent GenerateGroupsAndOptions(string optionLabel, IEnumerable<SelectListItem> selectList)
         {
-            return GenerateGroupsAndOptions(optionLabel: optionLabel, selectList: selectList, currentValues: null);
+            return GenerateGroupsAndOptions(optionLabel, selectList, currentValues: null);
         }
 
         private IHtmlContent GenerateGroupsAndOptions(

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

@@ -160,8 +160,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
         /// </remarks>
         public static IDictionary<string, object> AnonymousObjectToHtmlAttributes(object htmlAttributes)
         {
-            var dictionary = htmlAttributes as IDictionary<string, object>;
+            if (htmlAttributes is IDictionary<string, object> dictionary)
-            if (dictionary != null)
             {
                 return new Dictionary<string, object>(dictionary, StringComparer.OrdinalIgnoreCase);
             }
@@ -586,7 +585,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
         /// <inheritdoc />
         public IHtmlContent Raw(object value)
         {
-            return new HtmlString(value == null ? null : value.ToString());
+            return new HtmlString(value?.ToString());
         }
 
         /// <inheritdoc />
@@ -685,7 +684,11 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
         /// <inheritdoc />
         public IHtmlContent TextBox(string expression, object value, string format, object htmlAttributes)
         {
-            return GenerateTextBox(modelExplorer: null, expression: expression, value: value, format: format,
+            return GenerateTextBox(
+                modelExplorer: null,
+                expression: expression,
+                value: value,
+                format: format,
                 htmlAttributes: htmlAttributes);
         }
 
@@ -724,6 +727,15 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
                 return HtmlString.Empty;
             }
 
+            if (!hiddenForCheckbox.Attributes.ContainsKey("name") &&
+                checkbox.Attributes.TryGetValue("name", out var name))
+            {
+                // The checkbox and hidden elements should have the same name attribute value. Attributes will match
+                // if both are present because both have a generated value. Reach here in the special case where user
+                // provided a non-empty fallback name.
+                hiddenForCheckbox.MergeAttribute("name", name);
+            }
+
             if (ViewContext.FormContext.CanRenderAtEndOfForm)
             {
                 ViewContext.FormContext.EndOfFormContent.Add(hiddenForCheckbox);
@@ -861,7 +873,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
                 tagBuilder.WriteTo(ViewContext.Writer, _htmlEncoder);
             }
 
-            var shouldGenerateAntiforgery = antiforgery.HasValue ? antiforgery.Value : method != FormMethod.Get;
+            var shouldGenerateAntiforgery = antiforgery ?? method != FormMethod.Get;
             if (shouldGenerateAntiforgery)
             {
                 ViewContext.FormContext.EndOfFormContent.Add(_htmlGenerator.GenerateAntiforgery(ViewContext));
@@ -917,7 +929,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
                 tagBuilder.WriteTo(ViewContext.Writer, _htmlEncoder);
             }
 
-            var shouldGenerateAntiforgery = antiforgery.HasValue ? antiforgery.Value : method != FormMethod.Get;
+            var shouldGenerateAntiforgery = antiforgery ?? method != FormMethod.Get;
             if (shouldGenerateAntiforgery)
             {
                 ViewContext.FormContext.EndOfFormContent.Add(_htmlGenerator.GenerateAntiforgery(ViewContext));
@@ -969,9 +981,9 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
             var tagBuilder = _htmlGenerator.GenerateLabel(
                 ViewContext,
                 modelExplorer,
-                expression: expression,
+                expression,
-                labelText: labelText,
+                labelText,
-                htmlAttributes: htmlAttributes);
+                htmlAttributes);
             if (tagBuilder == null)
             {
                 return HtmlString.Empty;

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

@@ -22,7 +22,7 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
 {
     public class InputTagHelperTest
     {
-        public static TheoryData MultiAttributeCheckBoxData
+        public static TheoryData<TagHelperAttributeList, string> MultiAttributeCheckBoxData
         {
             get
             {
@@ -252,6 +252,317 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
             Assert.Equal(expectedPostElement, output.PostElement.GetContent());
         }
 
+        [Theory]
+        [InlineData("checkbox")]
+        [InlineData("hidden")]
+        [InlineData("number")]
+        [InlineData("password")]
+        [InlineData("text")]
+        public void Process_WithEmptyForName_Throws(string inputTypeName)
+        {
+            // Arrange
+            var expectedMessage = "The name of an HTML field cannot be null or empty. Instead use methods " +
+                "Microsoft.AspNetCore.Mvc.Rendering.IHtmlHelper.Editor or Microsoft.AspNetCore.Mvc.Rendering." +
+                "IHtmlHelper`1.EditorFor with a non-empty htmlFieldName argument value.";
+
+            var metadataProvider = new EmptyModelMetadataProvider();
+            var htmlGenerator = new TestableHtmlGenerator(metadataProvider);
+            var model = false;
+            var modelExplorer = metadataProvider.GetModelExplorerForType(typeof(bool), model);
+            var modelExpression = new ModelExpression(name: string.Empty, modelExplorer: modelExplorer);
+            var viewContext = TestableHtmlGenerator.GetViewContext(model, htmlGenerator, metadataProvider);
+            var tagHelper = new InputTagHelper(htmlGenerator)
+            {
+                For = modelExpression,
+                InputTypeName = inputTypeName,
+                ViewContext = viewContext,
+            };
+
+            var attributes = new TagHelperAttributeList
+            {
+                { "type", inputTypeName },
+            };
+
+            var context = new TagHelperContext(attributes, new Dictionary<object, object>(), "test");
+            var output = new TagHelperOutput(
+                "input",
+                new TagHelperAttributeList(),
+                getChildContentAsync: (useCachedResult, encoder) => Task.FromResult<TagHelperContent>(result: null))
+            {
+                TagMode = TagMode.SelfClosing,
+            };
+
+            // Act & Assert
+            ExceptionAssert.ThrowsArgument(
+                () => tagHelper.Process(context, output),
+                paramName: "expression",
+                exceptionMessage: expectedMessage);
+        }
+
+        [Fact]
+        public void Process_Radio_WithEmptyForName_Throws()
+        {
+            // Arrange
+            var expectedMessage = "The name of an HTML field cannot be null or empty. Instead use methods " +
+                "Microsoft.AspNetCore.Mvc.Rendering.IHtmlHelper.Editor or Microsoft.AspNetCore.Mvc.Rendering." +
+                "IHtmlHelper`1.EditorFor with a non-empty htmlFieldName argument value.";
+
+            var inputTypeName = "radio";
+            var metadataProvider = new EmptyModelMetadataProvider();
+            var htmlGenerator = new TestableHtmlGenerator(metadataProvider);
+            var model = 23;
+            var modelExplorer = metadataProvider.GetModelExplorerForType(typeof(int), model);
+            var modelExpression = new ModelExpression(name: string.Empty, modelExplorer: modelExplorer);
+            var viewContext = TestableHtmlGenerator.GetViewContext(model, htmlGenerator, metadataProvider);
+            var tagHelper = new InputTagHelper(htmlGenerator)
+            {
+                For = modelExpression,
+                InputTypeName = inputTypeName,
+                Value = "24",
+                ViewContext = viewContext,
+            };
+
+            var attributes = new TagHelperAttributeList
+            {
+                { "type", inputTypeName },
+                { "value", "24" },
+            };
+
+            var context = new TagHelperContext(attributes, new Dictionary<object, object>(), "test");
+            var output = new TagHelperOutput(
+                "input",
+                new TagHelperAttributeList(),
+                getChildContentAsync: (useCachedResult, encoder) => Task.FromResult<TagHelperContent>(result: null))
+            {
+                TagMode = TagMode.SelfClosing,
+            };
+
+            // Act & Assert
+            ExceptionAssert.ThrowsArgument(
+                () => tagHelper.Process(context, output),
+                paramName: "expression",
+                exceptionMessage: expectedMessage);
+        }
+
+        [Theory]
+        [InlineData("hidden")]
+        [InlineData("number")]
+        [InlineData("text")]
+        public void Process_WithEmptyForName_DoesNotThrow_WithName(string inputTypeName)
+        {
+            // Arrange
+            var expectedAttributeValue = "-expression-";
+            var expectedTagName = "input";
+            var expectedAttributes = new TagHelperAttributeList
+            {
+                { "name",  expectedAttributeValue },
+                { "type", inputTypeName },
+                { "value", "False" },
+            };
+
+            var metadataProvider = new EmptyModelMetadataProvider();
+            var htmlGenerator = new TestableHtmlGenerator(metadataProvider);
+            var model = false;
+            var modelExplorer = metadataProvider.GetModelExplorerForType(typeof(bool), model);
+            var modelExpression = new ModelExpression(name: string.Empty, modelExplorer: modelExplorer);
+            var viewContext = TestableHtmlGenerator.GetViewContext(model, htmlGenerator, metadataProvider);
+            viewContext.ClientValidationEnabled = false;
+
+            var tagHelper = new InputTagHelper(htmlGenerator)
+            {
+                For = modelExpression,
+                InputTypeName = inputTypeName,
+                Name = expectedAttributeValue,
+                ViewContext = viewContext,
+            };
+
+            var attributes = new TagHelperAttributeList
+            {
+                { "name", expectedAttributeValue },
+                { "type", inputTypeName },
+            };
+
+            var context = new TagHelperContext(attributes, new Dictionary<object, object>(), "test");
+            var output = new TagHelperOutput(
+                expectedTagName,
+                new TagHelperAttributeList(),
+                getChildContentAsync: (useCachedResult, encoder) => Task.FromResult<TagHelperContent>(result: null))
+            {
+                TagMode = TagMode.SelfClosing,
+            };
+
+            // Act
+            tagHelper.Process(context, output);
+
+            // Assert
+            Assert.Equal(expectedAttributes, output.Attributes);
+            Assert.False(output.IsContentModified);
+            Assert.Equal(expectedTagName, output.TagName);
+        }
+
+        [Fact]
+        public void Process_Checkbox_WithEmptyForName_DoesNotThrow_WithName()
+        {
+            // Arrange
+            var expectedAttributeValue = "-expression-";
+            var expectedPostElementContent = $"<input name=\"HtmlEncode[[{expectedAttributeValue}]]\" " +
+                "type=\"HtmlEncode[[hidden]]\" value=\"HtmlEncode[[false]]\" />";
+            var expectedTagName = "input";
+            var inputTypeName = "checkbox";
+            var expectedAttributes = new TagHelperAttributeList
+            {
+                { "name",  expectedAttributeValue },
+                { "type", inputTypeName },
+                { "value", "true" },
+            };
+
+            var metadataProvider = new EmptyModelMetadataProvider();
+            var htmlGenerator = new TestableHtmlGenerator(metadataProvider);
+            var model = false;
+            var modelExplorer = metadataProvider.GetModelExplorerForType(typeof(bool), model);
+            var modelExpression = new ModelExpression(name: string.Empty, modelExplorer: modelExplorer);
+            var viewContext = TestableHtmlGenerator.GetViewContext(model, htmlGenerator, metadataProvider);
+            viewContext.ClientValidationEnabled = false;
+
+            var tagHelper = new InputTagHelper(htmlGenerator)
+            {
+                For = modelExpression,
+                InputTypeName = inputTypeName,
+                Name = expectedAttributeValue,
+                ViewContext = viewContext,
+            };
+
+            var attributes = new TagHelperAttributeList
+            {
+                { "name", expectedAttributeValue },
+                { "type", inputTypeName },
+            };
+
+            var context = new TagHelperContext(attributes, new Dictionary<object, object>(), "test");
+            var output = new TagHelperOutput(
+                expectedTagName,
+                new TagHelperAttributeList(),
+                getChildContentAsync: (useCachedResult, encoder) => Task.FromResult<TagHelperContent>(result: null))
+            {
+                TagMode = TagMode.SelfClosing,
+            };
+
+            // Act
+            tagHelper.Process(context, output);
+
+            // Assert
+            Assert.Equal(expectedAttributes, output.Attributes);
+            Assert.False(output.IsContentModified);
+            Assert.Equal(expectedTagName, output.TagName);
+
+            Assert.False(viewContext.FormContext.HasEndOfFormContent);
+            Assert.Equal(expectedPostElementContent, HtmlContentUtilities.HtmlContentToString(output.PostElement));
+        }
+
+        [Fact]
+        public void Process_Password_WithEmptyForName_DoesNotThrow_WithName()
+        {
+            // Arrange
+            var expectedAttributeValue = "-expression-";
+            var expectedTagName = "input";
+            var inputTypeName = "password";
+            var expectedAttributes = new TagHelperAttributeList
+            {
+                { "name",  expectedAttributeValue },
+                { "type", inputTypeName },
+            };
+
+            var metadataProvider = new EmptyModelMetadataProvider();
+            var htmlGenerator = new TestableHtmlGenerator(metadataProvider);
+            var model = "password";
+            var modelExplorer = metadataProvider.GetModelExplorerForType(typeof(string), model);
+            var modelExpression = new ModelExpression(name: string.Empty, modelExplorer: modelExplorer);
+            var viewContext = TestableHtmlGenerator.GetViewContext(model, htmlGenerator, metadataProvider);
+            viewContext.ClientValidationEnabled = false;
+
+            var tagHelper = new InputTagHelper(htmlGenerator)
+            {
+                For = modelExpression,
+                InputTypeName = inputTypeName,
+                Name = expectedAttributeValue,
+                ViewContext = viewContext,
+            };
+
+            // Expect attributes to just pass through. Tag helper binds all input attributes and doesn't add any.
+            var context = new TagHelperContext(expectedAttributes, new Dictionary<object, object>(), "test");
+            var output = new TagHelperOutput(
+                expectedTagName,
+                new TagHelperAttributeList(),
+                getChildContentAsync: (useCachedResult, encoder) => Task.FromResult<TagHelperContent>(result: null))
+            {
+                TagMode = TagMode.SelfClosing,
+            };
+
+            // Act
+            tagHelper.Process(context, output);
+
+            // Assert
+            Assert.Equal(expectedAttributes, output.Attributes);
+            Assert.False(output.IsContentModified);
+            Assert.Equal(expectedTagName, output.TagName);
+        }
+
+        [Fact]
+        public void Process_Radio_WithEmptyForName_DoesNotThrow_WithName()
+        {
+            // Arrange
+            var expectedAttributeValue = "-expression-";
+            var expectedTagName = "input";
+            var inputTypeName = "radio";
+            var expectedAttributes = new TagHelperAttributeList
+            {
+                { "name",  expectedAttributeValue },
+                { "type", inputTypeName },
+                { "value", "24" },
+            };
+
+            var metadataProvider = new EmptyModelMetadataProvider();
+            var htmlGenerator = new TestableHtmlGenerator(metadataProvider);
+            var model = 23;
+            var modelExplorer = metadataProvider.GetModelExplorerForType(typeof(int), model);
+            var modelExpression = new ModelExpression(name: string.Empty, modelExplorer: modelExplorer);
+            var viewContext = TestableHtmlGenerator.GetViewContext(model, htmlGenerator, metadataProvider);
+            viewContext.ClientValidationEnabled = false;
+
+            var tagHelper = new InputTagHelper(htmlGenerator)
+            {
+                For = modelExpression,
+                InputTypeName = inputTypeName,
+                Name = expectedAttributeValue,
+                Value = "24",
+                ViewContext = viewContext,
+            };
+
+            var attributes = new TagHelperAttributeList
+            {
+                { "name", expectedAttributeValue },
+                { "type", inputTypeName },
+                { "value", "24" },
+            };
+
+            var context = new TagHelperContext(attributes, new Dictionary<object, object>(), "test");
+            var output = new TagHelperOutput(
+                expectedTagName,
+                new TagHelperAttributeList(),
+                getChildContentAsync: (useCachedResult, encoder) => Task.FromResult<TagHelperContent>(result: null))
+            {
+                TagMode = TagMode.SelfClosing,
+            };
+
+            // Act
+            tagHelper.Process(context, output);
+
+            // Assert
+            Assert.Equal(expectedAttributes, output.Attributes);
+            Assert.False(output.IsContentModified);
+            Assert.Equal(expectedTagName, output.TagName);
+        }
+
         // Top-level container (List<Model> or Model instance), immediate container type (Model or NestModel),
         // model accessor, expression path / id, expected value.
         public static TheoryData<object, Type, object, NameAndId, string> TestDataSet
@@ -1410,7 +1721,7 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
             };
 
             var metadataProvider = TestModelMetadataProvider.CreateDefaultProvider();
-            
+
             var model = new DateTime(
                 year: 2000,
                 month: 1,

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

@@ -6,12 +6,14 @@ using System.Collections;
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
+using Microsoft.AspNetCore.Html;
 using Microsoft.AspNetCore.Mvc.ModelBinding;
 using Microsoft.AspNetCore.Mvc.Rendering;
 using Microsoft.AspNetCore.Mvc.TagHelpers.Internal;
 using Microsoft.AspNetCore.Mvc.TestCommon;
 using Microsoft.AspNetCore.Mvc.ViewFeatures;
 using Microsoft.AspNetCore.Razor.TagHelpers;
+using Microsoft.AspNetCore.Testing;
 using Moq;
 using Xunit;
 
@@ -704,6 +706,132 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
             Assert.Same(currentValues, actualCurrentValues.Values);
         }
 
+        [Fact]
+        public void Process_WithEmptyForName_Throws()
+        {
+            // Arrange
+            var expectedMessage = "The name of an HTML field cannot be null or empty. Instead use methods " +
+                "Microsoft.AspNetCore.Mvc.Rendering.IHtmlHelper.Editor or Microsoft.AspNetCore.Mvc.Rendering." +
+                "IHtmlHelper`1.EditorFor with a non-empty htmlFieldName argument value.";
+            var expectedTagName = "select";
+
+            var metadataProvider = new EmptyModelMetadataProvider();
+            var htmlGenerator = new TestableHtmlGenerator(metadataProvider);
+            var model = "model-value";
+            var modelExplorer = metadataProvider.GetModelExplorerForType(typeof(string), model);
+            var modelExpression = new ModelExpression(name: string.Empty, modelExplorer: modelExplorer);
+            var viewContext = TestableHtmlGenerator.GetViewContext(model, htmlGenerator, metadataProvider);
+            var tagHelper = new SelectTagHelper(htmlGenerator)
+            {
+                For = modelExpression,
+                ViewContext = viewContext,
+            };
+
+            var context = new TagHelperContext(new TagHelperAttributeList(), new Dictionary<object, object>(), "test");
+            var output = new TagHelperOutput(
+                expectedTagName,
+                new TagHelperAttributeList(),
+                (_, __) => Task.FromResult<TagHelperContent>(new DefaultTagHelperContent()));
+
+            // Act & Assert
+            ExceptionAssert.ThrowsArgument(
+                () => tagHelper.Process(context, output),
+                paramName: "expression",
+                exceptionMessage: expectedMessage);
+        }
+
+        [Fact]
+        public void Process_WithEmptyForName_DoesNotThrow_WithName()
+        {
+            // Arrange
+            var expectedAttributeValue = "-expression-";
+            var expectedTagName = "select";
+
+            var metadataProvider = new EmptyModelMetadataProvider();
+            var htmlGenerator = new TestableHtmlGenerator(metadataProvider);
+            var model = "model-value";
+            var modelExplorer = metadataProvider.GetModelExplorerForType(typeof(string), model);
+            var modelExpression = new ModelExpression(name: string.Empty, modelExplorer: modelExplorer);
+            var viewContext = TestableHtmlGenerator.GetViewContext(model, htmlGenerator, metadataProvider);
+            var tagHelper = new SelectTagHelper(htmlGenerator)
+            {
+                For = modelExpression,
+                Name = expectedAttributeValue,
+                ViewContext = viewContext,
+            };
+
+            var attributes = new TagHelperAttributeList
+            {
+                { "name", expectedAttributeValue },
+            };
+
+            var context = new TagHelperContext(attributes, new Dictionary<object, object>(), "test");
+            var output = new TagHelperOutput(
+                expectedTagName,
+                new TagHelperAttributeList(),
+                (_, __) => Task.FromResult<TagHelperContent>(new DefaultTagHelperContent()));
+
+            // Act
+            tagHelper.Process(context, output);
+
+            // Assert
+            Assert.Equal(expectedTagName, output.TagName);
+            Assert.False(output.IsContentModified);
+
+            var attribute = Assert.Single(output.Attributes);
+            Assert.Equal("name", attribute.Name);
+            Assert.Equal(expectedAttributeValue, attribute.Value);
+        }
+
+        [Fact]
+        public void Process_PassesNameThrough_EvenIfNullFor()
+        {
+            // Arrange
+            var expectedAttributeValue = "-expression-";
+            var expectedTagName = "span";
+
+            var selectList = Array.Empty<SelectListItem>();
+            var generator = new Mock<IHtmlGenerator>(MockBehavior.Strict);
+            generator
+                .Setup(gen => gen.GenerateGroupsAndOptions(/* optionLabel: */ null, selectList))
+                .Returns(HtmlString.Empty)
+                .Verifiable();
+
+            var metadataProvider = new EmptyModelMetadataProvider();
+            var viewContext = TestableHtmlGenerator.GetViewContext(
+                model: null,
+                htmlGenerator: generator.Object,
+                metadataProvider: metadataProvider);
+
+            var tagHelper = new SelectTagHelper(generator.Object)
+            {
+                Items = selectList,
+                Name = expectedAttributeValue,
+                ViewContext = viewContext,
+            };
+
+            var attributes = new TagHelperAttributeList
+            {
+                { "name", expectedAttributeValue },
+            };
+
+            var tagHelperContext = new TagHelperContext(attributes, new Dictionary<object, object>(), "test");
+            var output = new TagHelperOutput(
+                expectedTagName,
+                new TagHelperAttributeList(),
+                (_, __) => Task.FromResult<TagHelperContent>(new DefaultTagHelperContent()));
+
+            // Act
+            tagHelper.Process(tagHelperContext, output);
+
+            // Assert
+            generator.VerifyAll();
+            Assert.Equal(expectedTagName, output.TagName);
+            var attribute = Assert.Single(output.Attributes);
+            Assert.Equal("name", attribute.Name);
+            Assert.Equal(expectedAttributeValue, attribute.Value);
+        }
+
         public class NameAndId
         {
             public NameAndId(string name, string id)

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

@@ -6,10 +6,10 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Mvc.ModelBinding;
-using Microsoft.AspNetCore.Mvc.Rendering;
 using Microsoft.AspNetCore.Mvc.TestCommon;
 using Microsoft.AspNetCore.Mvc.ViewFeatures;
 using Microsoft.AspNetCore.Razor.TagHelpers;
+using Microsoft.AspNetCore.Testing;
 using Xunit;
 
 namespace Microsoft.AspNetCore.Mvc.TagHelpers
@@ -160,6 +160,84 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
             Assert.Equal(expectedTagName, output.TagName);
         }
 
+        [Fact]
+        public void Process_WithEmptyForName_Throws()
+        {
+            // Arrange
+            var expectedMessage = "The name of an HTML field cannot be null or empty. Instead use methods " +
+                "Microsoft.AspNetCore.Mvc.Rendering.IHtmlHelper.Editor or Microsoft.AspNetCore.Mvc.Rendering." +
+                "IHtmlHelper`1.EditorFor with a non-empty htmlFieldName argument value.";
+            var expectedTagName = "textarea";
+
+            var metadataProvider = new EmptyModelMetadataProvider();
+            var htmlGenerator = new TestableHtmlGenerator(metadataProvider);
+            var model = "model-value";
+            var modelExplorer = metadataProvider.GetModelExplorerForType(typeof(string), model);
+            var modelExpression = new ModelExpression(name: string.Empty, modelExplorer: modelExplorer);
+            var viewContext = TestableHtmlGenerator.GetViewContext(model, htmlGenerator, metadataProvider);
+            var tagHelper = new TextAreaTagHelper(htmlGenerator)
+            {
+                For = modelExpression,
+                ViewContext = viewContext,
+            };
+
+            var context = new TagHelperContext(new TagHelperAttributeList(), new Dictionary<object, object>(), "test");
+            var output = new TagHelperOutput(
+                expectedTagName,
+                new TagHelperAttributeList(),
+                (_, __) => Task.FromResult<TagHelperContent>(new DefaultTagHelperContent()));
+
+            // Act & Assert
+            ExceptionAssert.ThrowsArgument(
+                () => tagHelper.Process(context, output),
+                paramName: "expression",
+                exceptionMessage: expectedMessage);
+        }
+
+        [Fact]
+        public void Process_WithEmptyForName_DoesNotThrow_WithName()
+        {
+            // Arrange
+            var expectedAttributeValue = "-expression-";
+            var expectedContent = Environment.NewLine + "HtmlEncode[[model-value]]";
+            var expectedTagName = "textarea";
+
+            var metadataProvider = new EmptyModelMetadataProvider();
+            var htmlGenerator = new TestableHtmlGenerator(metadataProvider);
+            var model = "model-value";
+            var modelExplorer = metadataProvider.GetModelExplorerForType(typeof(string), model);
+            var modelExpression = new ModelExpression(name: string.Empty, modelExplorer: modelExplorer);
+            var viewContext = TestableHtmlGenerator.GetViewContext(model, htmlGenerator, metadataProvider);
+            var tagHelper = new TextAreaTagHelper(htmlGenerator)
+            {
+                For = modelExpression,
+                Name = expectedAttributeValue,
+                ViewContext = viewContext,
+            };
+
+            var attributes = new TagHelperAttributeList
+            {
+                { "name", expectedAttributeValue },
+            };
+
+            var context = new TagHelperContext(attributes, new Dictionary<object, object>(), "test");
+            var output = new TagHelperOutput(
+                expectedTagName,
+                new TagHelperAttributeList(),
+                (_, __) => Task.FromResult<TagHelperContent>(new DefaultTagHelperContent()));
+
+            // Act
+            tagHelper.Process(context, output);
+
+            // Assert
+            Assert.Equal(expectedTagName, output.TagName);
+            Assert.Equal(expectedContent, HtmlContentUtilities.HtmlContentToString(output.Content));
+
+            var attribute = Assert.Single(output.Attributes);
+            Assert.Equal("name", attribute.Name);
+            Assert.Equal(expectedAttributeValue, attribute.Value);
+        }
+
         public class NameAndId
         {
             public NameAndId(string name, string id)

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

@@ -14,6 +14,7 @@ using Microsoft.AspNetCore.Mvc.ViewEngines;
 using Microsoft.AspNetCore.Mvc.ViewFeatures;
 using Microsoft.AspNetCore.Razor.TagHelpers;
 using Microsoft.AspNetCore.Routing;
+using Microsoft.AspNetCore.Testing;
 using Moq;
 using Xunit;
 
@@ -89,6 +90,151 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
             Assert.Equal(expectedTagName, output.TagName);
         }
 
+        [Fact]
+        public async Task ProcessAsync_WithEmptyNameFor_Throws()
+        {
+            // Arrange
+            var expectedTagName = "span";
+            var expectedMessage = "The name of an HTML field cannot be null or empty. Instead use methods " +
+                "Microsoft.AspNetCore.Mvc.Rendering.IHtmlHelper.Editor or Microsoft.AspNetCore.Mvc.Rendering." +
+                "IHtmlHelper`1.EditorFor with a non-empty htmlFieldName argument value.";
+
+            var metadataProvider = new EmptyModelMetadataProvider();
+            var modelExpression = CreateModelExpression(string.Empty);
+            var htmlGenerator = new TestableHtmlGenerator(metadataProvider);
+            var viewContext = TestableHtmlGenerator.GetViewContext(
+                model: null,
+                htmlGenerator: htmlGenerator,
+                metadataProvider: metadataProvider);
+
+            var validationMessageTagHelper = new ValidationMessageTagHelper(htmlGenerator)
+            {
+                For = modelExpression,
+                ViewContext = viewContext,
+            };
+
+            var tagHelperContext = new TagHelperContext(
+                expectedTagName,
+                new TagHelperAttributeList
+                {
+                    { "for", modelExpression },
+                },
+                new Dictionary<object, object>(),
+                "test");
+
+            var output = new TagHelperOutput(
+                expectedTagName,
+                new TagHelperAttributeList(),
+                (_, __) => Task.FromResult<TagHelperContent>(new DefaultTagHelperContent()));
+
+            // Act & Assert
+            await ExceptionAssert.ThrowsArgumentAsync(
+                () => validationMessageTagHelper.ProcessAsync(tagHelperContext, output),
+                paramName: "expression",
+                exceptionMessage: expectedMessage);
+        }
+
+        [Fact]
+        public async Task ProcessAsync_GeneratesExpectedOutput_WithEmptyNameFor_WithValidationFor()
+        {
+            // Arrange
+            var expectedAttributeValue = "-expression-";
+            var expectedTagName = "span";
+
+            var metadataProvider = new EmptyModelMetadataProvider();
+            var modelExpression = CreateModelExpression(string.Empty);
+            var htmlGenerator = new TestableHtmlGenerator(metadataProvider);
+            var viewContext = TestableHtmlGenerator.GetViewContext(
+                model: null,
+                htmlGenerator: htmlGenerator,
+                metadataProvider: metadataProvider);
+
+            var validationMessageTagHelper = new ValidationMessageTagHelper(htmlGenerator)
+            {
+                For = modelExpression,
+                ViewContext = viewContext,
+            };
+
+            var tagHelperContext = new TagHelperContext(
+                expectedTagName,
+                new TagHelperAttributeList
+                {
+                    { "for", modelExpression },
+                },
+                new Dictionary<object, object>(),
+                "test");
+
+            var output = new TagHelperOutput(
+                expectedTagName,
+                new TagHelperAttributeList
+                {
+                    { "data-valmsg-for", expectedAttributeValue },
+                },
+                (_, __) => Task.FromResult<TagHelperContent>(new DefaultTagHelperContent()));
+
+            validationMessageTagHelper.ViewContext = viewContext;
+
+            // Act
+            await validationMessageTagHelper.ProcessAsync(tagHelperContext, output);
+
+            // Assert
+            Assert.Equal(expectedTagName, output.TagName);
+            Assert.Collection(output.Attributes,
+                attribute =>
+                {
+                    Assert.Equal("data-valmsg-for", attribute.Name);
+                    Assert.Equal(expectedAttributeValue, attribute.Value);
+                },
+                attribute =>
+                {
+                    Assert.Equal("class", attribute.Name);
+                    Assert.Equal("field-validation-valid", attribute.Value);
+                },
+                attribute =>
+                {
+                    Assert.Equal("data-valmsg-replace", attribute.Name);
+                    Assert.Equal("true", attribute.Value);
+                });
+        }
+
+        [Fact]
+        public async Task ProcessAsync_PassesValidationForThrough_EvenIfNullFor()
+        {
+            // Arrange
+            var expectedAttributeValue = "-expression-";
+            var expectedTagName = "span";
+
+            // Generator is not used in this scenario.
+            var generator = new Mock<IHtmlGenerator>(MockBehavior.Strict);
+            var validationMessageTagHelper = new ValidationMessageTagHelper(generator.Object)
+            {
+                ViewContext = CreateViewContext(),
+            };
+
+            var tagHelperContext = new TagHelperContext(
+                expectedTagName,
+                new TagHelperAttributeList(),
+                new Dictionary<object, object>(),
+                "test");
+
+            var output = new TagHelperOutput(
+                expectedTagName,
+                new TagHelperAttributeList
+                {
+                    { "data-valmsg-for", expectedAttributeValue },
+                },
+                (_, __) => Task.FromResult<TagHelperContent>(new DefaultTagHelperContent()));
+
+            // Act
+            await validationMessageTagHelper.ProcessAsync(tagHelperContext, output);
+
+            // Assert
+            Assert.Equal(expectedTagName, output.TagName);
+            var attribute = Assert.Single(output.Attributes);
+            Assert.Equal("data-valmsg-for", attribute.Name);
+            Assert.Equal(expectedAttributeValue, attribute.Value);
+        }
+
         [Fact]
         public async Task ProcessAsync_CallsIntoGenerateValidationMessageWithExpectedParameters()
         {

test/Microsoft.AspNetCore.Mvc.ViewFeatures.Test/Rendering/HtmlHelperCheckboxTest.cs

@@ -95,7 +95,7 @@ namespace Microsoft.AspNetCore.Mvc.Rendering
                 "Microsoft.AspNetCore.Mvc.Rendering.IHtmlHelper.Editor or Microsoft.AspNetCore.Mvc.Rendering." +
                 "IHtmlHelper`1.EditorFor with a non-empty htmlFieldName argument value.";
 
-            var helper = DefaultTemplatesUtilities.GetHtmlHelper(GetTestModelViewData());
+            var helper = DefaultTemplatesUtilities.GetHtmlHelper(model: false);
 
             // Act & Assert
             ExceptionAssert.ThrowsArgument(
@@ -104,6 +104,29 @@ namespace Microsoft.AspNetCore.Mvc.Rendering
                 expected);
         }
 
+        [Fact]
+        public void CheckBoxWithNullExpression_DoesNotThrow_WithNameAttribute()
+        {
+            // Arrange
+            var expected = @"<input class=""HtmlEncode[[some-class]]"" name=""HtmlEncode[[-expression-]]"" " +
+                @"type=""HtmlEncode[[checkbox]]"" value=""HtmlEncode[[true]]"" /><input " +
+                @"name=""HtmlEncode[[-expression-]]"" type=""HtmlEncode[[hidden]]"" value=""HtmlEncode[[false]]"" />";
+
+            var helper = DefaultTemplatesUtilities.GetHtmlHelper(model: false);
+            helper.ViewContext.ClientValidationEnabled = false;
+            var attributes = new Dictionary<string, object>
+            {
+                { "class", "some-class"},
+                { "name", "-expression-" },
+            };
+
+            // Act
+            var html = helper.CheckBox(null, isChecked: false, htmlAttributes: attributes);
+
+            // Assert
+            Assert.Equal(expected, HtmlContentUtilities.HtmlContentToString(html));
+        }
+
         [Fact]
         public void CheckBoxCheckedWithOnlyName_GeneratesExpectedValue()
         {
@@ -413,12 +436,17 @@ namespace Microsoft.AspNetCore.Mvc.Rendering
             var requiredMessage = ValidationAttributeUtil.GetRequiredErrorMessage("Boolean");
             var expected =
                 $@"<input data-val=""HtmlEncode[[true]]"" data-val-required=""HtmlEncode[[{requiredMessage}]]"" " +
-                @"id=""HtmlEncode[[MyPrefix]]"" name=""HtmlEncode[[MyPrefix]]"" Property3=""HtmlEncode[[Property3Value]]"" " +
+                @"id=""HtmlEncode[[MyPrefix]]"" name=""HtmlEncode[[MyPrefix]]"" " +
-                @"type=""HtmlEncode[[checkbox]]"" value=""HtmlEncode[[true]]"" /><input name=""HtmlEncode[[MyPrefix]]"" type=""HtmlEncode[[hidden]]"" " +
+                @"Property3=""HtmlEncode[[Property3Value]]"" type=""HtmlEncode[[checkbox]]"" " +
-                @"value=""HtmlEncode[[false]]"" />";
+                @"value=""HtmlEncode[[true]]"" /><input name=""HtmlEncode[[MyPrefix]]"" " +
+                @"type=""HtmlEncode[[hidden]]"" value=""HtmlEncode[[false]]"" />";
             var helper = DefaultTemplatesUtilities.GetHtmlHelper(model: false);
-            var attributes = new Dictionary<string, object> { { "Property3", "Property3Value" } };
             helper.ViewContext.ViewData.TemplateInfo.HtmlFieldPrefix = "MyPrefix";
+            var attributes = new Dictionary<string, object>
+            {
+                { "Property3", "Property3Value" },
+                { "name", "-expression-" }, // overridden
+            };
 
             // Act
             var html = helper.CheckBox(string.Empty, isChecked: false, htmlAttributes: attributes);
@@ -589,10 +617,15 @@ namespace Microsoft.AspNetCore.Mvc.Rendering
             var expected =
                 $@"<input data-val=""HtmlEncode[[true]]"" data-val-required=""HtmlEncode[[{requiredMessage}]]"" " +
                 @"id=""HtmlEncode[[Property1]]"" name=""HtmlEncode[[Property1]]"" " +
-                @"Property3=""HtmlEncode[[Property3Value]]"" type=""HtmlEncode[[checkbox]]"" value=""HtmlEncode[[true]]"" /><input " +
+                @"Property3=""HtmlEncode[[Property3Value]]"" type=""HtmlEncode[[checkbox]]"" " +
-                @"name=""HtmlEncode[[Property1]]"" type=""HtmlEncode[[hidden]]"" value=""HtmlEncode[[false]]"" />";
+                @"value=""HtmlEncode[[true]]"" /><input name=""HtmlEncode[[Property1]]"" " +
+                @"type=""HtmlEncode[[hidden]]"" value=""HtmlEncode[[false]]"" />";
             var helper = DefaultTemplatesUtilities.GetHtmlHelper(GetTestModelViewData());
-            var attributes = new Dictionary<string, object> { { "Property3", "Property3Value" } };
+            var attributes = new Dictionary<string, object>
+            {
+                { "Property3", "Property3Value" },
+                { "name", "-expression-" }, // overridden
+            };
 
             // Act
             var html = helper.CheckBoxFor(m => m.Property1, attributes);

test/Microsoft.AspNetCore.Mvc.ViewFeatures.Test/Rendering/HtmlHelperHiddenTest.cs

@@ -15,19 +15,36 @@ namespace Microsoft.AspNetCore.Mvc.Rendering
 {
     public class HtmlHelperHiddenTest
     {
-        public static IEnumerable<object[]> HiddenWithAttributesData
+        public static TheoryData<object, string> HiddenWithAttributesData
         {
             get
             {
-                var expected1 = @"<input baz=""HtmlEncode[[BazValue]]"" id=""HtmlEncode[[Property1]]"" name=""HtmlEncode[[Property1]]"" type=""HtmlEncode[[hidden]]"" " +
+                var expected1 = @"<input baz=""HtmlEncode[[BazValue]]"" id=""HtmlEncode[[Property1]]"" " +
+                    @"name=""HtmlEncode[[Property1]]"" type=""HtmlEncode[[hidden]]"" " +
                     @"value=""HtmlEncode[[ModelStateValue]]"" />";
-                yield return new object[] { new Dictionary<string, object> { { "baz", "BazValue" } }, expected1 };
+                var expected2 = @"<input foo-baz=""HtmlEncode[[BazValue]]"" id=""HtmlEncode[[Property1]]"" " +
-                yield return new object[] { new { baz = "BazValue" }, expected1 };
+                    @"name=""HtmlEncode[[Property1]]"" type=""HtmlEncode[[hidden]]"" " +
+                    @"value=""HtmlEncode[[ModelStateValue]]"" />";
+                var htmlAttributes1 = new Dictionary<string, object>
+                {
+                    { "baz", "BazValue" },
+                    { "name", "-expression-" }, // overridden
+                };
+                var htmlAttributes2 = new
+                {
+                    baz = "BazValue",
+                    name = "-expression-", // overridden
+                };
 
-                var expected2 = @"<input foo-baz=""HtmlEncode[[BazValue]]"" id=""HtmlEncode[[Property1]]"" name=""HtmlEncode[[Property1]]"" type=""HtmlEncode[[hidden]]"" " +
+                var data = new TheoryData<object, string>
-                    @"value=""HtmlEncode[[ModelStateValue]]"" />";
+                {
-                yield return new object[] { new Dictionary<string, object> { { "foo-baz", "BazValue" } }, expected2 };
+                    { htmlAttributes1, expected1 },
-                yield return new object[] { new { foo_baz = "BazValue" }, expected2 };
+                    { htmlAttributes2, expected1 },
+                    { new Dictionary<string, object> { { "foo-baz", "BazValue" } }, expected2 },
+                    { new { foo_baz = "BazValue" }, expected2 }
+                };
+
+                return data;
             }
         }
 
@@ -408,7 +425,7 @@ namespace Microsoft.AspNetCore.Mvc.Rendering
         public void HiddenWithEmptyNameAndPrefixThrows()
         {
             // Arrange
-            var helper = DefaultTemplatesUtilities.GetHtmlHelper(GetViewDataWithModelStateAndModelAndViewDataValues());
+            var helper = DefaultTemplatesUtilities.GetHtmlHelper("model-value");
             var attributes = new Dictionary<string, object>
             {
                 { "class", "some-class"}
@@ -419,11 +436,31 @@ namespace Microsoft.AspNetCore.Mvc.Rendering
 
             // Act and Assert
             ExceptionAssert.ThrowsArgument(
-                () => helper.Hidden(string.Empty, string.Empty, attributes),
+                () => helper.Hidden(expression: string.Empty, value: null, htmlAttributes: attributes),
                 "expression",
                 expected);
         }
 
+        [Fact]
+        public void HiddenWithEmptyNameAndPrefix_DoesNotThrow_WithNameAttribute()
+        {
+            // Arrange
+            var expected = @"<input class=""HtmlEncode[[some-class]]"" name=""HtmlEncode[[-expression-]]"" " +
+                @"type=""HtmlEncode[[hidden]]"" value=""HtmlEncode[[model-value]]"" />";
+            var helper = DefaultTemplatesUtilities.GetHtmlHelper("model-value");
+            var attributes = new Dictionary<string, object>
+            {
+                { "class", "some-class"},
+                { "name", "-expression-" },
+            };
+
+            // Act
+            var result = helper.Hidden(expression: string.Empty, value: null, htmlAttributes: attributes);
+
+            // Assert
+            Assert.Equal(expected, HtmlContentUtilities.HtmlContentToString(result));
+        }
+
         [Fact]
         public void HiddenWithViewDataErrors_GeneratesExpectedValue()
         {

test/Microsoft.AspNetCore.Mvc.ViewFeatures.Test/Rendering/HtmlHelperPasswordTest.cs

@@ -15,39 +15,58 @@ namespace Microsoft.AspNetCore.Mvc.Rendering
 {
     public class HtmlHelperPasswordTest
     {
-        public static IEnumerable<object[]> PasswordWithViewDataAndAttributesData
+        public static TheoryData<object> HtmlAttributeData
         {
             get
             {
-                var attributes1 = new Dictionary<string, object>
+                return new TheoryData<object>
                 {
-                    { "test-key", "test-value" },
+                    new Dictionary<string, object>
-                    { "value", "attribute-value" }
+                    {
+                        { "name", "-expression-" }, // overridden
+                        { "test-key", "test-value" },
+                        { "value", "attribute-value" },
+                    },
+                    new
+                    {
+                        name = "-expression-", // overridden
+                        test_key = "test-value",
+                        value = "attribute-value",
+                    },
                 };
+            }
+        }
 
-                var attributes2 = new { test_key = "test-value", value = "attribute-value" };
+        public static TheoryData<ViewDataDictionary<PasswordModel>, object> PasswordWithViewDataAndAttributesData
+        {
+            get
+            {
+                var nullModelViewData = GetViewDataWithNullModelAndNonEmptyViewData();
+                var viewData = GetViewDataWithModelStateAndModelAndViewDataValues();
+                viewData.Model.Property1 = "does-not-get-used";
 
-                var vdd = GetViewDataWithModelStateAndModelAndViewDataValues();
+                var data = new TheoryData<ViewDataDictionary<PasswordModel>, object>();
-                vdd.Model.Property1 = "does-not-get-used";
+                foreach (var items in HtmlAttributeData)
-                yield return new object[] { vdd, attributes1 };
+                {
-                yield return new object[] { vdd, attributes2 };
+                    data.Add(viewData, items[0]);
+                    data.Add(nullModelViewData, items[0]);
+                }
 
-                var nullModelVdd = GetViewDataWithNullModelAndNonEmptyViewData();
+                return data;
-                yield return new object[] { nullModelVdd, attributes1 };
-                yield return new object[] { nullModelVdd, attributes2 };
             }
         }
 
         [Theory]
         [MemberData(nameof(PasswordWithViewDataAndAttributesData))]
         public void Password_UsesAttributeValueWhenValueArgumentIsNull(
-            ViewDataDictionary<PasswordModel> vdd,
+            ViewDataDictionary<PasswordModel> viewData,
             object attributes)
         {
             // Arrange
-            var expected = @"<input id=""HtmlEncode[[Property1]]"" name=""HtmlEncode[[Property1]]"" test-key=""HtmlEncode[[test-value]]"" type=""HtmlEncode[[password]]"" " +
+            var expected = @"<input id=""HtmlEncode[[Property1]]"" name=""HtmlEncode[[Property1]]"" " +
-                           @"value=""HtmlEncode[[attribute-value]]"" />";
+                @"test-key=""HtmlEncode[[test-value]]"" type=""HtmlEncode[[password]]"" " +
-            var helper = DefaultTemplatesUtilities.GetHtmlHelper(vdd);
+                @"value=""HtmlEncode[[attribute-value]]"" />";
+            var helper = DefaultTemplatesUtilities.GetHtmlHelper(viewData);
 
             // Act
             var result = helper.Password("Property1", value: null, htmlAttributes: attributes);
@@ -59,13 +78,14 @@ namespace Microsoft.AspNetCore.Mvc.Rendering
         [Theory]
         [MemberData(nameof(PasswordWithViewDataAndAttributesData))]
         public void Password_UsesExplicitValue_IfSpecified(
-            ViewDataDictionary<PasswordModel> vdd,
+            ViewDataDictionary<PasswordModel> viewData,
             object attributes)
         {
             // Arrange
-            var expected = @"<input id=""HtmlEncode[[Property1]]"" name=""HtmlEncode[[Property1]]"" test-key=""HtmlEncode[[test-value]]"" type=""HtmlEncode[[password]]"" " +
+            var expected = @"<input id=""HtmlEncode[[Property1]]"" name=""HtmlEncode[[Property1]]"" " +
-                           @"value=""HtmlEncode[[explicit-value]]"" />";
+                @"test-key=""HtmlEncode[[test-value]]"" type=""HtmlEncode[[password]]"" " +
-            var helper = DefaultTemplatesUtilities.GetHtmlHelper(vdd);
+                @"value=""HtmlEncode[[explicit-value]]"" />";
+            var helper = DefaultTemplatesUtilities.GetHtmlHelper(viewData);
 
             // Act
             var result = helper.Password("Property1", "explicit-value", attributes);
@@ -128,20 +148,35 @@ namespace Microsoft.AspNetCore.Mvc.Rendering
         public void PasswordWithEmptyNameAndPrefixThrows()
         {
             // Arrange
-            var helper = DefaultTemplatesUtilities.GetHtmlHelper(GetViewDataWithModelStateAndModelAndViewDataValues());
+            var helper = DefaultTemplatesUtilities.GetHtmlHelper("model-value");
-            var name = string.Empty;
+            var expression = string.Empty;
-            var value = string.Empty;
             var expectedMessage = "The name of an HTML field cannot be null or empty. Instead use methods " +
                 "Microsoft.AspNetCore.Mvc.Rendering.IHtmlHelper.Editor or Microsoft.AspNetCore.Mvc.Rendering." +
                 "IHtmlHelper`1.EditorFor with a non-empty htmlFieldName argument value.";
 
             // Act and Assert
             ExceptionAssert.ThrowsArgument(
-                () => helper.Password(name, value, htmlAttributes: null),
+                () => helper.Password(expression, value: null, htmlAttributes: null),
                 "expression",
                 expectedMessage);
         }
 
+        [Fact]
+        public void PasswordWithEmptyNameAndPrefix_DoesNotThrow_WithNameAttribute()
+        {
+            // Arrange
+            var expected = @"<input name=""HtmlEncode[[-expression-]]"" type=""HtmlEncode[[password]]"" />";
+            var helper = DefaultTemplatesUtilities.GetHtmlHelper("model-value");
+            var expression = string.Empty;
+            var htmlAttributes = new { name = "-expression-" };
+
+            // Act
+            var result = helper.Password(expression, value: null, htmlAttributes: htmlAttributes);
+
+            // Assert
+            Assert.Equal(expected, HtmlContentUtilities.HtmlContentToString(result));
+        }
+
         [Fact]
         public void Password_UsesModelStateErrors_ButDoesNotUseModelOrViewDataOrModelStateForValueAttribute()
         {
@@ -218,14 +253,13 @@ namespace Microsoft.AspNetCore.Mvc.Rendering
         }
 
         [Theory]
-        [MemberData(nameof(PasswordWithViewDataAndAttributesData))]
+        [MemberData(nameof(HtmlAttributeData))]
-        public void PasswordForWithAttributes_GeneratesExpectedValue(
+        public void PasswordForWithAttributes_GeneratesExpectedValue(object htmlAttributes)
-            ViewDataDictionary<PasswordModel> vdd,
-            object htmlAttributes)
         {
             // Arrange
-            var expected = @"<input id=""HtmlEncode[[Property1]]"" name=""HtmlEncode[[Property1]]"" test-key=""HtmlEncode[[test-value]]"" type=""HtmlEncode[[password]]"" " +
+            var expected = @"<input id=""HtmlEncode[[Property1]]"" name=""HtmlEncode[[Property1]]"" " +
-                           @"value=""HtmlEncode[[attribute-value]]"" />";
+                @"test-key=""HtmlEncode[[test-value]]"" type=""HtmlEncode[[password]]"" " +
+                @"value=""HtmlEncode[[attribute-value]]"" />";
             var helper = DefaultTemplatesUtilities.GetHtmlHelper(GetViewDataWithModelStateAndModelAndViewDataValues());
             helper.ViewData.Model.Property1 = "test";
 

test/Microsoft.AspNetCore.Mvc.ViewFeatures.Test/Rendering/HtmlHelperRadioButtonExtensionsTest.cs

@@ -5,6 +5,7 @@ using Microsoft.AspNetCore.Mvc.ModelBinding;
 using Microsoft.AspNetCore.Mvc.Rendering;
 using Microsoft.AspNetCore.Mvc.TestCommon;
 using Microsoft.AspNetCore.Mvc.ViewFeatures;
+using Microsoft.AspNetCore.Testing;
 using Xunit;
 
 namespace Microsoft.AspNetCore.Mvc.Core
@@ -122,13 +123,19 @@ namespace Microsoft.AspNetCore.Mvc.Core
         {
             // Arrange
             var helper = DefaultTemplatesUtilities.GetHtmlHelper();
+            var htmlAttributes = new
+            {
+                attr = "value",
+                name = "-expression-", // overridden
+            };
 
             // Act
-            var radioButtonResult = helper.RadioButton("Property1", value: "myvalue", htmlAttributes: new { attr = "value" });
+            var radioButtonResult = helper.RadioButton("Property1", "myvalue", htmlAttributes);
 
             // Assert
             Assert.Equal(
-                "<input attr=\"HtmlEncode[[value]]\" id=\"HtmlEncode[[Property1]]\" name=\"HtmlEncode[[Property1]]\" type=\"HtmlEncode[[radio]]\" value=\"HtmlEncode[[myvalue]]\" />",
+                "<input attr=\"HtmlEncode[[value]]\" id=\"HtmlEncode[[Property1]]\" " +
+                "name=\"HtmlEncode[[Property1]]\" type=\"HtmlEncode[[radio]]\" value=\"HtmlEncode[[myvalue]]\" />",
                 HtmlContentUtilities.HtmlContentToString(radioButtonResult));
         }
 
@@ -137,13 +144,61 @@ namespace Microsoft.AspNetCore.Mvc.Core
         {
             // Arrange
             var helper = DefaultTemplatesUtilities.GetHtmlHelper();
+            var htmlAttributes = new
+            {
+                attr = "value",
+                name = "-expression-", // overridden
+            };
 
             // Act
-            var radioButtonForResult = helper.RadioButtonFor(m => m.Property1, value: "myvalue", htmlAttributes: new { attr = "value" });
+            var radioButtonForResult = helper.RadioButtonFor(m => m.Property1, "myvalue", htmlAttributes);
 
             // Assert
             Assert.Equal(
-                "<input attr=\"HtmlEncode[[value]]\" id=\"HtmlEncode[[Property1]]\" name=\"HtmlEncode[[Property1]]\" type=\"HtmlEncode[[radio]]\" value=\"HtmlEncode[[myvalue]]\" />",
+                "<input attr=\"HtmlEncode[[value]]\" id=\"HtmlEncode[[Property1]]\" " +
+                "name=\"HtmlEncode[[Property1]]\" type=\"HtmlEncode[[radio]]\" value=\"HtmlEncode[[myvalue]]\" />",
+                HtmlContentUtilities.HtmlContentToString(radioButtonForResult));
+        }
+
+        [Fact]
+        public void RadioButtonFor_Throws_IfFullNameEmpty()
+        {
+            // Arrange
+            var expectedMessage = "The name of an HTML field cannot be null or empty. Instead use methods " +
+                "Microsoft.AspNetCore.Mvc.Rendering.IHtmlHelper.Editor or Microsoft.AspNetCore.Mvc.Rendering." +
+                "IHtmlHelper`1.EditorFor with a non-empty htmlFieldName argument value.";
+
+            var helper = DefaultTemplatesUtilities.GetHtmlHelper("anotherValue");
+            var htmlAttributes = new
+            {
+                attr = "value",
+            };
+
+            // Act & Assert
+            ExceptionAssert.ThrowsArgument(
+                () => helper.RadioButtonFor(m => m, "myvalue", htmlAttributes),
+                paramName: "expression",
+                exceptionMessage: expectedMessage);
+        }
+
+        [Fact]
+        public void RadioButtonFor_DoesNotThrow_IfFullNameEmpty_WithNameAttribute()
+        {
+            // Arrange
+            var helper = DefaultTemplatesUtilities.GetHtmlHelper("anotherValue");
+            var htmlAttributes = new
+            {
+                attr = "value",
+                name = "-expression-",
+            };
+
+            // Act
+            var radioButtonForResult = helper.RadioButtonFor(m => m, "myvalue", htmlAttributes);
+
+            // Assert
+            Assert.Equal(
+                "<input attr=\"HtmlEncode[[value]]\" " +
+                "name=\"HtmlEncode[[-expression-]]\" type=\"HtmlEncode[[radio]]\" value=\"HtmlEncode[[myvalue]]\" />",
                 HtmlContentUtilities.HtmlContentToString(radioButtonForResult));
         }
 

test/Microsoft.AspNetCore.Mvc.ViewFeatures.Test/Rendering/HtmlHelperTextBoxExtensionsTest.cs

@@ -5,6 +5,7 @@ using Microsoft.AspNetCore.Mvc.ModelBinding;
 using Microsoft.AspNetCore.Mvc.Rendering;
 using Microsoft.AspNetCore.Mvc.TestCommon;
 using Microsoft.AspNetCore.Mvc.ViewFeatures;
+using Microsoft.AspNetCore.Testing;
 using Xunit;
 
 namespace Microsoft.AspNetCore.Mvc.Core
@@ -108,17 +109,27 @@ namespace Microsoft.AspNetCore.Mvc.Core
         public void TextBox_UsesSpecifiedHtmlAttributes()
         {
             // Arrange
-            var metadataProvider = new EmptyModelMetadataProvider();
+            var htmlAttributes = new
-            var helper = DefaultTemplatesUtilities.GetHtmlHelper(new ViewDataDictionary<TestModel>(metadataProvider));
+            {
+                attr = "value",
+                name = "-expression-", // overridden
+            };
+
+            var model = new TestModel
+            {
+                Property1 = "propValue"
+            };
+
+            var helper = DefaultTemplatesUtilities.GetHtmlHelper(model);
             helper.ViewContext.ClientValidationEnabled = false;
-            helper.ViewData.Model = new TestModel { Property1 = "propValue" };
 
             // Act
-            var textBoxResult = helper.TextBox("Property1", value: "myvalue", htmlAttributes: new { attr = "value" });
+            var textBoxResult = helper.TextBox("Property1", "myvalue", htmlAttributes);
 
             // Assert
             Assert.Equal(
-                "<input attr=\"HtmlEncode[[value]]\" id=\"HtmlEncode[[Property1]]\" name=\"HtmlEncode[[Property1]]\" type=\"HtmlEncode[[text]]\" value=\"HtmlEncode[[myvalue]]\" />",
+                "<input attr=\"HtmlEncode[[value]]\" id=\"HtmlEncode[[Property1]]\" " +
+                "name=\"HtmlEncode[[Property1]]\" type=\"HtmlEncode[[text]]\" value=\"HtmlEncode[[myvalue]]\" />",
                 HtmlContentUtilities.HtmlContentToString(textBoxResult));
         }
 
@@ -126,17 +137,73 @@ namespace Microsoft.AspNetCore.Mvc.Core
         public void TextBoxFor_UsesSpecifiedHtmlAttributes()
         {
             // Arrange
-            var metadataProvider = new EmptyModelMetadataProvider();
+            var htmlAttributes = new
-            var helper = DefaultTemplatesUtilities.GetHtmlHelper(new ViewDataDictionary<TestModel>(metadataProvider));
+            {
+                attr = "value",
+                name = "-expression-", // overridden
+            };
+
+            var model = new TestModel
+            {
+                Property1 = "propValue"
+            };
+
+            var helper = DefaultTemplatesUtilities.GetHtmlHelper(model);
             helper.ViewContext.ClientValidationEnabled = false;
-            helper.ViewData.Model = new TestModel { Property1 = "propValue" };
 
             // Act
-            var textBoxForResult = helper.TextBoxFor(m => m.Property1, htmlAttributes: new { attr = "value" });
+            var textBoxForResult = helper.TextBoxFor(m => m.Property1, htmlAttributes);
 
             // Assert
             Assert.Equal(
-                "<input attr=\"HtmlEncode[[value]]\" id=\"HtmlEncode[[Property1]]\" name=\"HtmlEncode[[Property1]]\" type=\"HtmlEncode[[text]]\" value=\"HtmlEncode[[propValue]]\" />",
+                "<input attr=\"HtmlEncode[[value]]\" id=\"HtmlEncode[[Property1]]\" " +
+                "name=\"HtmlEncode[[Property1]]\" type=\"HtmlEncode[[text]]\" value=\"HtmlEncode[[propValue]]\" />",
+                HtmlContentUtilities.HtmlContentToString(textBoxForResult));
+        }
+
+        [Fact]
+        public void TextBoxFor_Throws_IfFullNameEmpty()
+        {
+            // Arrange
+            var expectedMessage = "The name of an HTML field cannot be null or empty. Instead use methods " +
+                "Microsoft.AspNetCore.Mvc.Rendering.IHtmlHelper.Editor or Microsoft.AspNetCore.Mvc.Rendering." +
+                "IHtmlHelper`1.EditorFor with a non-empty htmlFieldName argument value.";
+
+            var htmlAttributes = new
+            {
+                attr = "value",
+            };
+
+            var helper = DefaultTemplatesUtilities.GetHtmlHelper("propValue");
+            helper.ViewContext.ClientValidationEnabled = false;
+
+            // Act & Assert
+            ExceptionAssert.ThrowsArgument(
+                () => helper.TextBoxFor(m => m, htmlAttributes),
+                paramName: "expression",
+                exceptionMessage: expectedMessage);
+        }
+
+        [Fact]
+        public void TextBoxFor_DoesNotThrow_IfFullNameEmpty_WithNameAttribute()
+        {
+            // Arrange
+            var htmlAttributes = new
+            {
+                attr = "value",
+                name = "-expression-",
+            };
+
+            var helper = DefaultTemplatesUtilities.GetHtmlHelper("propValue");
+            helper.ViewContext.ClientValidationEnabled = false;
+
+            // Act
+            var textBoxForResult = helper.TextBoxFor(m => m, htmlAttributes);
+
+            // Assert
+            Assert.Equal(
+                "<input attr=\"HtmlEncode[[value]]\" " +
+                "name=\"HtmlEncode[[-expression-]]\" type=\"HtmlEncode[[text]]\" value=\"HtmlEncode[[propValue]]\" />",
                 HtmlContentUtilities.HtmlContentToString(textBoxForResult));
         }
 

test/Microsoft.AspNetCore.Mvc.ViewFeatures.Test/ViewFeatures/DefaultHtmlGeneratorTest.cs

@@ -69,7 +69,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
         }
 
         [Fact]
-        public void GetCurrentValues_WithNullExpression_Throws()
+        public void GetCurrentValues_WithNullExpression_DoesNotThrow()
         {
             // Arrange
             var metadataProvider = new TestModelMetadataProvider();
@@ -77,19 +77,8 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
             var viewContext = GetViewContext<Model>(model: null, metadataProvider: metadataProvider);
             var modelExplorer = metadataProvider.GetModelExplorerForType(typeof(string), model: null);
 
-            var expected = "The name of an HTML field cannot be null or empty. Instead use " +
+            // Act and Assert (does not throw).
-                "methods Microsoft.AspNetCore.Mvc.Rendering.IHtmlHelper.Editor or Microsoft.AspNetCore.Mvc.Rendering." +
+            htmlGenerator.GetCurrentValues(viewContext, modelExplorer, expression: null, allowMultiple: true);
-                "IHtmlHelper`1.EditorFor with a non-empty htmlFieldName argument value.";
-
-            // Act and assert
-            ExceptionAssert.ThrowsArgument(
-                () => htmlGenerator.GetCurrentValues(
-                    viewContext,
-                    modelExplorer,
-                    expression: null,
-                    allowMultiple: true),
-                "expression",
-                expected);
         }
 
         [Fact]
@@ -105,20 +94,49 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
                 "Microsoft.AspNetCore.Mvc.Rendering.IHtmlHelper.Editor or Microsoft.AspNetCore.Mvc.Rendering." +
                 "IHtmlHelper`1.EditorFor with a non-empty htmlFieldName argument value.";
 
-            // Act and assert
+            // Act and Assert
             ExceptionAssert.ThrowsArgument(
                 () => htmlGenerator.GenerateSelect(
                     viewContext,
                     modelExplorer,
                     "label",
-                    null,
+                    expression: null,
-                    new List<SelectListItem>(),
+                    selectList: new List<SelectListItem>(),
-                    true,
+                    allowMultiple: true,
-                    null),
+                    htmlAttributes: null),
                 "expression",
                 expected);
         }
 
+        [Fact]
+        public void GenerateSelect_WithNullExpression_WithNameAttribute_DoesNotThrow()
+        {
+            // Arrange
+            var expected = "-expression-";
+            var metadataProvider = new TestModelMetadataProvider();
+            var htmlGenerator = GetGenerator(metadataProvider);
+            var viewContext = GetViewContext<Model>(model: null, metadataProvider: metadataProvider);
+            var modelExplorer = metadataProvider.GetModelExplorerForType(typeof(string), model: null);
+            var htmlAttributes = new Dictionary<string, object>
+            {
+                { "name", expected },
+            };
+
+            // Act
+            var tagBuilder = htmlGenerator.GenerateSelect(
+                viewContext,
+                modelExplorer,
+                "label",
+                expression: null,
+                selectList: new List<SelectListItem>(),
+                allowMultiple: true,
+                htmlAttributes: htmlAttributes);
+
+            // Assert
+            var attribute = Assert.Single(tagBuilder.Attributes, a => a.Key == "name");
+            Assert.Equal(expected, attribute.Value);
+        }
+
         [Fact]
         public void GenerateTextArea_WithNullExpression_Throws()
         {
@@ -132,19 +150,47 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
                 "Microsoft.AspNetCore.Mvc.Rendering.IHtmlHelper.Editor or Microsoft.AspNetCore.Mvc.Rendering." +
                 "IHtmlHelper`1.EditorFor with a non-empty htmlFieldName argument value.";
 
-            // Act and assert
+            // Act and Assert
             ExceptionAssert.ThrowsArgument(
                 () => htmlGenerator.GenerateTextArea(
                     viewContext,
                     modelExplorer,
-                    null,
+                    expression: null,
-                    1,
+                    rows: 1,
-                    1,
+                    columns: 1,
-                    null),
+                    htmlAttributes: null),
                 "expression",
                 expected);
         }
 
+        [Fact]
+        public void GenerateTextArea_WithNullExpression_WithNameAttribute_DoesNotThrow()
+        {
+            // Arrange
+            var expected = "-expression-";
+            var metadataProvider = new TestModelMetadataProvider();
+            var htmlGenerator = GetGenerator(metadataProvider);
+            var viewContext = GetViewContext<Model>(model: null, metadataProvider: metadataProvider);
+            var modelExplorer = metadataProvider.GetModelExplorerForType(typeof(string), model: null);
+            var htmlAttributes = new Dictionary<string, object>
+            {
+                { "name", expected },
+            };
+
+            // Act
+            var tagBuilder = htmlGenerator.GenerateTextArea(
+                viewContext,
+                modelExplorer,
+                expression: null,
+                rows: 1,
+                columns: 1,
+                htmlAttributes: htmlAttributes);
+
+            // Assert
+            var attribute = Assert.Single(tagBuilder.Attributes, a => a.Key == "name");
+            Assert.Equal(expected, attribute.Value);
+        }
+
         [Fact]
         public void GenerateValidationMessage_WithNullExpression_Throws()
         {
@@ -158,13 +204,47 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
                 "Microsoft.AspNetCore.Mvc.Rendering.IHtmlHelper.Editor or Microsoft.AspNetCore.Mvc.Rendering." +
                 "IHtmlHelper`1.EditorFor with a non-empty htmlFieldName argument value.";
 
-            // Act and assert
+            // Act and Assert
             ExceptionAssert.ThrowsArgument(
-                () => htmlGenerator.GenerateValidationMessage(viewContext, null, null, "Message", "tag", null),
+                () => htmlGenerator.GenerateValidationMessage(
+                    viewContext,
+                    modelExplorer: null,
+                    expression: null,
+                    message: "Message",
+                    tag: "tag",
+                    htmlAttributes: null),
                 "expression",
                 expected);
         }
 
+        [Fact]
+        public void GenerateValidationMessage_WithNullExpression_WithValidationForAttribute_DoesNotThrow()
+        {
+            // Arrange
+            var expected = "-expression-";
+            var metadataProvider = new TestModelMetadataProvider();
+            var htmlGenerator = GetGenerator(metadataProvider);
+            var viewContext = GetViewContext<Model>(model: null, metadataProvider: metadataProvider);
+            var modelExplorer = metadataProvider.GetModelExplorerForType(typeof(string), model: null);
+            var htmlAttributes = new Dictionary<string, object>
+            {
+                { "data-valmsg-for", expected },
+            };
+
+            // Act
+            var tagBuilder = htmlGenerator.GenerateValidationMessage(
+                viewContext,
+                modelExplorer: null,
+                expression: null,
+                message: "Message",
+                tag: "tag",
+                htmlAttributes: htmlAttributes);
+
+            // Assert
+            var attribute = Assert.Single(tagBuilder.Attributes, a => a.Key == "data-valmsg-for");
+            Assert.Equal(expected, attribute.Value);
+        }
+
         [Theory]
         [InlineData(false)]
         [InlineData(true)]