Porting the ValidationMessage changes to suit WebFX requirements.

src/Microsoft.AspNet.Mvc.Core/Rendering/Html/HtmlHelper.cs

@@ -38,7 +38,7 @@ namespace Microsoft.AspNet.Mvc.Rendering
         /// Initializes a new instance of the <see cref="HtmlHelper"/> class.
         /// </summary>
         public HtmlHelper(
-            [NotNull] IViewEngine viewEngine, 
+            [NotNull] IViewEngine viewEngine,
             [NotNull] IModelMetadataProvider metadataProvider,
             [NotNull] IUrlHelper urlHelper, 
             [NotNull] AntiForgery antiForgeryInstance)
@@ -98,13 +98,13 @@ namespace Microsoft.AspNet.Mvc.Rendering
 
         /// <inheritdoc />
         public HtmlString ActionLink(
-            [NotNull] string linkText, 
+            [NotNull] string linkText,
-            string actionName, 
+            string actionName,
-            string controllerName, 
+            string controllerName,
-            string protocol, 
+            string protocol,
-            string hostname, 
+            string hostname,
-            string fragment, 
+            string fragment,
-            object routeValues, 
+            object routeValues,
             object htmlAttributes)
         {
             var url = _urlHelper.Action(actionName, controllerName, routeValues);
@@ -508,6 +508,46 @@ namespace Microsoft.AspNet.Mvc.Rendering
             return divBuilder.ToHtmlString(TagRenderMode.Normal);
         }
 
+        public HtmlString ValidationMessage(string name, string message, object htmlAttributes)
+        {
+            ModelState modelState;
+            ViewData.ModelState.TryGetValue(name, out modelState);
+
+            ModelErrorCollection errors = null;
+            if (modelState != null)
+            {
+                errors = modelState.Errors;
+            }
+
+            bool hasError = errors != null && errors.Any();
+            if (!hasError && !ViewContext.UnobtrusiveJavaScriptEnabled)
+            {
+                return null;
+            }
+            else
+            {
+                string error = null;
+                if (hasError)
+                {
+                    error = message ?? errors.First().ErrorMessage;
+                }
+
+                var tagBuilder = new TagBuilder("span") { InnerHtml = Encode(error) };
+                tagBuilder.MergeAttributes(AnonymousObjectToHtmlAttributes(htmlAttributes));
+
+                if (ViewContext.UnobtrusiveJavaScriptEnabled)
+                {
+                    bool replaceValidationMessageContents = string.IsNullOrEmpty(message);
+                    tagBuilder.MergeAttribute("data-valmsg-for", name);
+                    tagBuilder.MergeAttribute("data-valmsg-replace",
+                        replaceValidationMessageContents.ToString().ToLowerInvariant());
+                }
+
+                tagBuilder.AddCssClass(hasError ? ValidationMessageCssClassName : ValidationMessageValidCssClassName);
+                return tagBuilder.ToHtmlString(TagRenderMode.Normal);
+            }
+        }
+
         /// <summary>
         /// Returns the HTTP method that handles form input (GET or POST) as a string.
         /// </summary>

src/Microsoft.AspNet.Mvc.Core/Rendering/HtmlHelperValidationExtensions.cs

@@ -56,39 +56,40 @@ namespace Microsoft.AspNet.Mvc.Rendering
                 htmlAttributes: htmlAttributes);
         }
 
-        private IHtmlString BuildValidationMessage(string name, string message, IDictionary<string, object> htmlAttributes)
+        public static HtmlString ValidationMessage<TModel>([NotNull] this IHtmlHelper<TModel> htmlHelper,
+            string modelName)
         {
-            var modelState = ModelState[name];
+            return ValidationMessage(htmlHelper, modelName, message: null, htmlAttributes: null);
-            IEnumerable<string> errors = null;
+        }
-            if (modelState != null)
-            {
-                errors = modelState.Errors;
-            }
-            bool hasError = errors != null && errors.Any();
-            if (!hasError && !UnobtrusiveJavaScriptEnabled)
-            {
-                // If unobtrusive validation is enabled, we need to generate an empty span with the "val-for" attribute"
-                return null;
-            }
-            else
-            {
-                string error = null;
-                if (hasError)
-                {
-                    error = message ?? errors.First();
-                }
 
-                TagBuilder tagBuilder = new TagBuilder("span") { InnerHtml = Encode(error) };
+        public static HtmlString ValidationMessage<TModel>([NotNull] this IHtmlHelper<TModel> htmlHelper,
-                tagBuilder.MergeAttributes(htmlAttributes);
+            string modelName, string message)
-                if (UnobtrusiveJavaScriptEnabled)
+        {
-                {
+            return ValidationMessage(htmlHelper, modelName, message, htmlAttributes: null);
-                    bool replaceValidationMessageContents = String.IsNullOrEmpty(message);
+        }
-                    tagBuilder.MergeAttribute("data-valmsg-for", name);
+
-                    tagBuilder.MergeAttribute("data-valmsg-replace", replaceValidationMessageContents.ToString().ToLowerInvariant());
+        public static HtmlString ValidationMessage<TModel>([NotNull] this IHtmlHelper<TModel> htmlHelper,
-                }
+            string modelName, object htmlAttributes)
-                tagBuilder.AddCssClass(hasError ? ValidationMessageCssClassName : ValidationMessageValidCssClassName);
+        {
-                return tagBuilder.ToHtmlString(TagRenderMode.Normal);
+            return ValidationMessage(htmlHelper, modelName, message: null, htmlAttributes: htmlAttributes);
-            }
+        }
+
+        public static HtmlString ValidationMessage<TModel>([NotNull] this IHtmlHelper<TModel> htmlHelper,
+            string modelName, IDictionary<string, object> htmlAttributes)
+        {
+            return ValidationMessage(htmlHelper, modelName, message: null, htmlAttributes: htmlAttributes);
+        }
+
+        public static HtmlString ValidationMessage<TModel>([NotNull] this IHtmlHelper<TModel> htmlHelper,
+            string modelName, string message, IDictionary<string, object> htmlAttributes)
+        {
+            return htmlHelper.ValidationMessage(modelName, message, htmlAttributes);
+        }
+
+        public static HtmlString ValidationMessage<TModel>([NotNull] this IHtmlHelper<TModel> htmlHelper,
+            string modelName, string message, object htmlAttributes)
+        {
+            return htmlHelper.ValidationMessage(modelName, message, htmlAttributes);
         }
     }
 }

src/Microsoft.AspNet.Mvc.Core/Rendering/IHtmlHelperOfT.cs

@@ -223,6 +223,16 @@ namespace Microsoft.AspNet.Mvc.Rendering
         HtmlString TextBoxFor<TProperty>([NotNull] Expression<Func<TModel, TProperty>> expression, string format,
             IDictionary<string, object> htmlAttributes);
 
+        /// <summary>
+        /// Returns the validation message if an error exists in the <see cref="ModelStateDictionary"/> object.
+        /// </summary>
+        /// <param name="modelName">The name of the property that is being validated.</param>
+        /// <param name="message">The message to be displayed if the specified field contains an error.</param>
+        /// <param name="htmlAttributes">Dictionary that contains the HTML attributes which should
+        /// be applied on the element</param>
+        /// <returns></returns>
+        HtmlString ValidationMessage(string modelName, string message, object htmlAttributes);
+
         /// <summary>
         /// Returns the model value for the given expression <paramref name="expression"/>.
         /// </summary>