From 52ce83db9e2a23348b99519b5ca59e2d30fff60a Mon Sep 17 00:00:00 2001
From: "N. Taylor Mullen" <nimullen@microsoft.com>
Date: Wed, 2 Apr 2014 15:25:45 -0700
Subject: [PATCH] Implement DisplayFor Html Helper.

Essentially add extension methods and call through to infrastructure.
---
 .../Html/HtmlHelper.cs                        | 18 +++++++++
 .../TemplatedHelpers/DisplayForExtensions.cs  | 39 +++++++++++++++++++
 .../IHtmlHelperOfT.cs                         | 15 +++++++
 3 files changed, 72 insertions(+)
 create mode 100644 src/Microsoft.AspNet.Mvc.Rendering/Html/TemplatedHelpers/DisplayForExtensions.cs

diff --git a/src/Microsoft.AspNet.Mvc.Rendering/Html/HtmlHelper.cs b/src/Microsoft.AspNet.Mvc.Rendering/Html/HtmlHelper.cs
index a87a9e92b4..f4a266fa98 100644
--- a/src/Microsoft.AspNet.Mvc.Rendering/Html/HtmlHelper.cs
+++ b/src/Microsoft.AspNet.Mvc.Rendering/Html/HtmlHelper.cs
@@ -175,6 +175,24 @@ namespace Microsoft.AspNet.Mvc.Rendering
                                            additionalViewData);
         }
 
+        public virtual HtmlString DisplayFor<TModel, TValue>(Expression<Func<TModel, TValue>> expression,
+                                                             string templateName,
+                                                             string htmlFieldName,
+                                                             object additionalViewData)
+        {
+            var templateBuilder = new TemplateBuilder(ViewContext,
+                                                      ViewData,
+                                                      ExpressionMetadataProvider.FromLambdaExpression(expression, (ViewDataDictionary<TModel>)ViewData, MetadataProvider),
+                                                      htmlFieldName ?? ExpressionHelper.GetExpressionText(expression),
+                                                      templateName,
+                                                      readOnly: true,
+                                                      additionalViewData: additionalViewData);
+
+            var templateResult = templateBuilder.Build();
+
+            return new HtmlString(templateResult);
+        }
+
         /// <inheritdoc />
         public virtual HtmlString Name(string name)
         {
diff --git a/src/Microsoft.AspNet.Mvc.Rendering/Html/TemplatedHelpers/DisplayForExtensions.cs b/src/Microsoft.AspNet.Mvc.Rendering/Html/TemplatedHelpers/DisplayForExtensions.cs
new file mode 100644
index 0000000000..f300357d25
--- /dev/null
+++ b/src/Microsoft.AspNet.Mvc.Rendering/Html/TemplatedHelpers/DisplayForExtensions.cs
@@ -0,0 +1,39 @@
+using System;
+using System.Diagnostics.CodeAnalysis;
+using System.Linq.Expressions;
+
+namespace Microsoft.AspNet.Mvc.Rendering
+{
+    public static class DisplayForExtensions
+    {
+        [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures", Justification = "This is an appropriate nesting of generic types")]
+        public static HtmlString DisplayFor<TModel, TValue>(this IHtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression)
+        {
+            return html.DisplayFor<TModel, TValue>(expression, templateName: null, htmlFieldName: null, additionalViewData: null);
+        }
+
+        [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures", Justification = "This is an appropriate nesting of generic types")]
+        public static HtmlString DisplayFor<TModel, TValue>(this IHtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression, object additionalViewData)
+        {
+            return html.DisplayFor<TModel, TValue>(expression, templateName: null, htmlFieldName: null, additionalViewData: additionalViewData);
+        }
+
+        [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures", Justification = "This is an appropriate nesting of generic types")]
+        public static HtmlString DisplayFor<TModel, TValue>(this IHtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression, string templateName)
+        {
+            return html.DisplayFor<TModel, TValue>(expression, templateName, htmlFieldName: null, additionalViewData: null);
+        }
+
+        [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures", Justification = "This is an appropriate nesting of generic types")]
+        public static HtmlString DisplayFor<TModel, TValue>(this IHtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression, string templateName, object additionalViewData)
+        {
+            return html.DisplayFor<TModel, TValue>(expression, templateName, htmlFieldName: null, additionalViewData: additionalViewData);
+        }
+
+        [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures", Justification = "This is an appropriate nesting of generic types")]
+        public static HtmlString DisplayFor<TModel, TValue>(this IHtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression, string templateName, string htmlFieldName)
+        {
+            return html.DisplayFor<TModel, TValue>(expression, templateName: templateName, htmlFieldName: htmlFieldName, additionalViewData: null);
+        }
+    }
+}
diff --git a/src/Microsoft.AspNet.Mvc.Rendering/IHtmlHelperOfT.cs b/src/Microsoft.AspNet.Mvc.Rendering/IHtmlHelperOfT.cs
index cb28633a92..7431c353e8 100644
--- a/src/Microsoft.AspNet.Mvc.Rendering/IHtmlHelperOfT.cs
+++ b/src/Microsoft.AspNet.Mvc.Rendering/IHtmlHelperOfT.cs
@@ -51,6 +51,21 @@ namespace Microsoft.AspNet.Mvc.Rendering
                            string htmlFieldName,
                            object additionalViewData);
 
+        /// <summary>
+        /// Returns HTML markup for each property in the object that is represented by the specified expression, using the template, an HTML field ID, and additional view data.
+        /// </summary>
+        /// <typeparam name="TDisplayModel">The type of the model.</typeparam>
+        /// <typeparam name="TValue">The type of the value.</typeparam>
+        /// <param name="expression">An expression that identifies the object that contains the properties to display.</param>
+        /// <param name="templateName">The name of the template that is used to render the object.</param>
+        /// <param name="htmlFieldName">A string that is used to disambiguate the names of HTML input elements that are rendered for properties that have the same name.</param>
+        /// <param name="additionalViewData">An anonymous object that can contain additional view data that will be merged into the <see cref="ViewDataDictionary{TModel}"/> instance that is created for the template.</param>
+        /// <returns>The HTML markup for each property in the object that is represented by the expression.</returns>
+        HtmlString DisplayFor<TDisplayModel, TValue>(Expression<Func<TDisplayModel, TValue>> expression,
+                                              string templateName,
+                                              string htmlFieldName,
+                                              object additionalViewData);
+
         /// <summary>
         /// Converts the value of the specified object to an HTML-encoded string.
         /// </summary>