Add `BeginRouteForm()` HTML helper

- refactor `DefaultHtmlGenerator.GenerateForm()` to support new method

nits:
- correct XML comments
- add a few more code comments

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

@@ -6,11 +6,9 @@ using System.Collections;
 using System.Collections.Generic;
 using System.Diagnostics.Contracts;
 using System.Globalization;
-using System.IO;
 using System.Linq;
 using System.Net;
 using System.Text;
-using System.Threading.Tasks;
 using Microsoft.AspNet.Mvc.Core;
 using Microsoft.AspNet.Mvc.ModelBinding;
 using Microsoft.AspNet.Mvc.Rendering.Expressions;
@@ -157,21 +155,17 @@ namespace Microsoft.AspNet.Mvc.Rendering
             string method,
             object htmlAttributes)
         {
-            var tagBuilder = new TagBuilder("form");
-            tagBuilder.MergeAttributes(GetHtmlAttributeDictionaryOrNull(htmlAttributes));
-
             var defaultMethod = false;
             if (string.IsNullOrEmpty(method))
             {
                 defaultMethod = true;
-                method = FormMethod.Post.ToString();
             }
             else if (string.Equals(method, FormMethod.Post.ToString(), StringComparison.OrdinalIgnoreCase))
             {
                 defaultMethod = true;
             }
 
-            string formAction;
+            string action;
             if (actionName == null && controllerName == null && routeValues == null && defaultMethod &&
                 htmlAttributes == null)
             {
@@ -179,20 +173,28 @@ namespace Microsoft.AspNet.Mvc.Rendering
                 // parameters. Also reachable in the even-more-unusual case that user called another BeginForm()
                 // overload with default argument values.
                 var request = viewContext.HttpContext.Request;
-                formAction = request.PathBase + request.Path + request.QueryString;
+                action = request.PathBase + request.Path + request.QueryString;
             }
             else
             {
-                formAction = _urlHelper.Action(action: actionName, controller: controllerName, values: routeValues);
+                action = _urlHelper.Action(action: actionName, controller: controllerName, values: routeValues);
             }
 
-            // action is implicitly generated, so htmlAttributes take precedence.
+            return GenerateFormCore(viewContext, action, method, htmlAttributes);
-            tagBuilder.MergeAttribute("action", formAction);
+        }
 
-            // method is an explicit parameter, so it takes precedence over the htmlAttributes.
+        /// <inheritdoc />
-            tagBuilder.MergeAttribute("method", method, replaceExisting: true);
+        public TagBuilder GenerateRouteForm(
+            [NotNull]ViewContext viewContext,
+            string routeName,
+            object routeValues,
+            string method,
+            object htmlAttributes)
+        {
+            var action =
+                _urlHelper.RouteUrl(routeName, values: routeValues, protocol: null, host: null, fragment: null);
 
-            return tagBuilder;
+            return GenerateFormCore(viewContext, action, method, htmlAttributes);
         }
 
         /// <inheritdoc />
@@ -780,6 +782,44 @@ namespace Microsoft.AspNet.Mvc.Rendering
             return null;
         }
 
+        /// <summary>
+        /// Generate a &lt;form&gt; element.
+        /// </summary>
+        /// <param name="viewContext">A <see cref="ViewContext"/> instance for the current scope.</param>
+        /// <param name="action">The URL where the form-data should be submitted.</param>
+        /// <param name="method">The HTTP method for processing the form, either GET or POST.</param>
+        /// <param name="htmlAttributes">
+        /// An <see cref="object"/> that contains the HTML attributes for the element. Alternatively, an
+        /// <see cref="IDictionary{string, object}"/> instance containing the HTML attributes.
+        /// </param>
+        /// <returns>
+        /// A <see cref="TagBuilder"/> instance for the &lt;/form&gt; element.
+        /// </returns>
+        protected virtual TagBuilder GenerateFormCore(
+            [NotNull] ViewContext viewContext,
+            string action,
+            string method,
+            object htmlAttributes)
+        {
+            var tagBuilder = new TagBuilder("form");
+            tagBuilder.MergeAttributes(GetHtmlAttributeDictionaryOrNull(htmlAttributes));
+
+            // action is implicitly generated from other parameters, so htmlAttributes take precedence.
+            tagBuilder.MergeAttribute("action", action);
+
+            if (string.IsNullOrEmpty(method))
+            {
+                // Occurs only when called from a tag helper.
+                method = FormMethod.Post.ToString();
+            }
+
+            // For tag helpers, htmlAttributes will be null; replaceExisting value does not matter.
+            // method is an explicit parameter to HTML helpers, so it takes precedence over the htmlAttributes.
+            tagBuilder.MergeAttribute("method", method, replaceExisting: true);
+
+            return tagBuilder;
+        }
+
         protected virtual TagBuilder GenerateInput(
             [NotNull] ViewContext viewContext,
             InputType inputType,

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

@@ -3,7 +3,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Globalization;
 using System.IO;
 using System.Linq;
 using System.Text;
@@ -218,6 +217,12 @@ namespace Microsoft.AspNet.Mvc.Rendering
             return GenerateForm(actionName, controllerName, routeValues, method, htmlAttributes);
         }
 
+        /// <inheritdoc />
+        public MvcForm BeginRouteForm(string routeName, object routeValues, FormMethod method, object htmlAttributes)
+        {
+            return GenerateRouteForm(routeName, routeValues, method, htmlAttributes);
+        }
+
         /// <inheritdoc />
         public void EndForm()
         {
@@ -611,8 +616,8 @@ namespace Microsoft.AspNet.Mvc.Rendering
         }
 
         /// <summary>
-        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form,
+        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form, the
-        /// the request will be processed by an action method.
+        /// <paramref name="actionName"/> method will process the request.
         /// </summary>
         /// <param name="actionName">The name of the action method.</param>
         /// <param name="controllerName">The name of the controller.</param>
@@ -623,10 +628,12 @@ namespace Microsoft.AspNet.Mvc.Rendering
         /// <see cref="IDictionary{string, object}"/> instance containing the route parameters.
         /// </param>
         /// <param name="method">The HTTP method for processing the form, either GET or POST.</param>
-        /// <param name="htmlAttributes">An <see cref="IDictionary{string, object}"/> instance containing HTML
+        /// <param name="htmlAttributes">
-        /// attributes to set for the element.</param>
+        /// An <see cref="object"/> that contains the HTML attributes for the element. Alternatively, an
+        /// <see cref="IDictionary{string, object}"/> instance containing the HTML attributes.
+        /// </param>
         /// <returns>
-        /// An <see cref="MvcForm"/> instance which emits the &lt;/form&gt; end tag when disposed.
+        /// An <see cref="MvcForm"/> instance which renders the &lt;/form&gt; end tag when disposed.
         /// </returns>
         /// <remarks>
         /// In this context, "renders" means the method writes its output using <see cref="ViewContext.Writer"/>.
@@ -653,6 +660,49 @@ namespace Microsoft.AspNet.Mvc.Rendering
             return CreateForm();
         }
 
+        /// <summary>
+        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form, the
+        /// <paramref name="routeName"/> route will forward the request to an action method.
+        /// </summary>
+        /// <param name="routeName">The name of the route.</param>
+        /// <param name="routeValues">
+        /// An <see cref="object"/> that contains the parameters for a route. The parameters are retrieved through
+        /// reflection by examining the properties of the <see cref="object"/>. This <see cref="object"/> is typically
+        /// created using <see cref="object"/> initializer syntax. Alternatively, an
+        /// <see cref="IDictionary{string, object}"/> instance containing the route parameters.
+        /// </param>
+        /// <param name="method">The HTTP method for processing the form, either GET or POST.</param>
+        /// <param name="htmlAttributes">
+        /// An <see cref="object"/> that contains the HTML attributes for the element. Alternatively, an
+        /// <see cref="IDictionary{string, object}"/> instance containing the HTML attributes.
+        /// </param>
+        /// <returns>
+        /// An <see cref="MvcForm"/> instance which renders the &lt;/form&gt; end tag when disposed.
+        /// </returns>
+        /// <remarks>
+        /// In this context, "renders" means the method writes its output using <see cref="ViewContext.Writer"/>.
+        /// </remarks>
+        protected virtual MvcForm GenerateRouteForm(
+            string routeName,
+            object routeValues,
+            FormMethod method,
+            object htmlAttributes)
+        {
+            var tagBuilder = _htmlGenerator.GenerateRouteForm(
+                ViewContext,
+                routeName,
+                routeValues,
+                GetFormMethodString(method),
+                htmlAttributes);
+            if (tagBuilder != null)
+            {
+                ViewContext.Writer.Write(tagBuilder.ToString(TagRenderMode.StartTag));
+            }
+
+            return CreateForm();
+        }
+
+
         protected virtual HtmlString GenerateHidden(
             ModelMetadata metadata,
             string name,

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

@@ -49,9 +49,10 @@ namespace Microsoft.AspNet.Mvc.Rendering
             string name);
 
         /// <summary>
-        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form,
+        /// Generate a &lt;form&gt; element. When the user submits the form, the <paramref name="actionName"/> method
-        /// the request will be processed by an action method.
+        /// will process the request.
         /// </summary>
+        /// <param name="viewContext">A <see cref="ViewContext"/> instance for the current scope.</param>
         /// <param name="actionName">The name of the action method.</param>
         /// <param name="controllerName">The name of the controller.</param>
         /// <param name="routeValues">
@@ -61,14 +62,13 @@ namespace Microsoft.AspNet.Mvc.Rendering
         /// <see cref="IDictionary{string, object}"/> instance containing the route parameters.
         /// </param>
         /// <param name="method">The HTTP method for processing the form, either GET or POST.</param>
-        /// <param name="htmlAttributes">An <see cref="IDictionary{string, object}"/> instance containing HTML
+        /// <param name="htmlAttributes">
-        /// attributes to set for the element.</param>
+        /// An <see cref="object"/> that contains the HTML attributes for the element. Alternatively, an
+        /// <see cref="IDictionary{string, object}"/> instance containing the HTML attributes.
+        /// </param>
         /// <returns>
-        /// An <see cref="MvcForm"/> instance which emits the &lt;/form&gt; end tag when disposed.
+        /// A <see cref="TagBuilder"/> instance for the &lt;/form&gt; element.
         /// </returns>
-        /// <remarks>
-        /// In this context, "renders" means the method writes its output using <see cref="ViewContext.Writer"/>.
-        /// </remarks>
         TagBuilder GenerateForm(
             [NotNull] ViewContext viewContext,
             string actionName,
@@ -77,6 +77,33 @@ namespace Microsoft.AspNet.Mvc.Rendering
             string method,
             object htmlAttributes);
 
+        /// <summary>
+        /// Generate a &lt;form&gt; element. When the user submits the form, the <paramref name="routeName"/> route
+        /// will forward the request to an action method.
+        /// </summary>
+        /// <param name="viewContext">A <see cref="ViewContext"/> instance for the current scope.</param>
+        /// <param name="routeName">The name of the route.</param>
+        /// <param name="routeValues">
+        /// An <see cref="object"/> that contains the parameters for a route. The parameters are retrieved through
+        /// reflection by examining the properties of the <see cref="object"/>. This <see cref="object"/> is typically
+        /// created using <see cref="object"/> initializer syntax. Alternatively, an
+        /// <see cref="IDictionary{string, object}"/> instance containing the route parameters.
+        /// </param>
+        /// <param name="method">The HTTP method for processing the form, either GET or POST.</param>
+        /// <param name="htmlAttributes">
+        /// An <see cref="object"/> that contains the HTML attributes for the element. Alternatively, an
+        /// <see cref="IDictionary{string, object}"/> instance containing the HTML attributes.
+        /// </param>
+        /// <returns>
+        /// A <see cref="TagBuilder"/> instance for the &lt;/form&gt; element.
+        /// </returns>
+        TagBuilder GenerateRouteForm(
+            [NotNull] ViewContext viewContext,
+            string routeName,
+            object routeValues,
+            string method,
+            object htmlAttributes);
+
         TagBuilder GenerateHidden(
             [NotNull] ViewContext viewContext,
             ModelMetadata metadata,

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

@@ -28,8 +28,8 @@ namespace Microsoft.AspNet.Mvc.Rendering
         }
 
         /// <summary>
-        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form,
+        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form, the
-        /// the request will be processed by an action method.
+        /// current action method will process the request.
         /// </summary>
         /// <param name="htmlHelper">The <see cref="IHtmlHelper"/> instance this method extends.</param>
         /// <param name="method">The HTTP method for processing the form, either GET or POST.</param>
@@ -46,8 +46,8 @@ namespace Microsoft.AspNet.Mvc.Rendering
         }
 
         /// <summary>
-        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form,
+        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form, the
-        /// the request will be processed by an action method.
+        /// current action method will process the request.
         /// </summary>
         /// <param name="htmlHelper">The <see cref="IHtmlHelper"/> instance this method extends.</param>
         /// <param name="method">The HTTP method for processing the form, either GET or POST.</param>
@@ -72,8 +72,8 @@ namespace Microsoft.AspNet.Mvc.Rendering
         }
 
         /// <summary>
-        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form,
+        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form, the
-        /// the request will be processed by an action method.
+        /// current action method will process the request.
         /// </summary>
         /// <param name="htmlHelper">The <see cref="IHtmlHelper"/> instance this method extends.</param>
         /// <param name="routeValues">
@@ -96,8 +96,8 @@ namespace Microsoft.AspNet.Mvc.Rendering
         }
 
         /// <summary>
-        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form,
+        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form, the
-        /// the request will be processed by an action method.
+        /// <paramref name="actionName"/> method will process the request.
         /// </summary>
         /// <param name="htmlHelper">The <see cref="IHtmlHelper"/> instance this method extends.</param>
         /// <param name="actionName">The name of the action method.</param>
@@ -118,8 +118,8 @@ namespace Microsoft.AspNet.Mvc.Rendering
         }
 
         /// <summary>
-        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form,
+        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form, the
-        /// the request will be processed by an action method.
+        /// <paramref name="actionName"/> method will process the request.
         /// </summary>
         /// <param name="htmlHelper">The <see cref="IHtmlHelper"/> instance this method extends.</param>
         /// <param name="actionName">The name of the action method.</param>
@@ -148,8 +148,8 @@ namespace Microsoft.AspNet.Mvc.Rendering
         }
 
         /// <summary>
-        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form,
+        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form, the
-        /// the request will be processed by an action method.
+        /// <paramref name="actionName"/> method will process the request.
         /// </summary>
         /// <param name="htmlHelper">The <see cref="IHtmlHelper"/> instance this method extends.</param>
         /// <param name="actionName">The name of the action method.</param>
@@ -172,8 +172,8 @@ namespace Microsoft.AspNet.Mvc.Rendering
         }
 
         /// <summary>
-        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form,
+        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form, the
-        /// the request will be processed by an action method.
+        /// <paramref name="actionName"/> method will process the request.
         /// </summary>
         /// <param name="htmlHelper">The <see cref="IHtmlHelper"/> instance this method extends.</param>
         /// <param name="actionName">The name of the action method.</param>
@@ -204,8 +204,8 @@ namespace Microsoft.AspNet.Mvc.Rendering
         }
 
         /// <summary>
-        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form,
+        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form, the
-        /// the request will be processed by an action method.
+        /// <paramref name="actionName"/> method will process the request.
         /// </summary>
         /// <param name="htmlHelper">The <see cref="IHtmlHelper"/> instance this method extends.</param>
         /// <param name="actionName">The name of the action method.</param>
@@ -232,5 +232,161 @@ namespace Microsoft.AspNet.Mvc.Rendering
             return htmlHelper.BeginForm(actionName, controllerName, routeValues: null,
                                         method: method, htmlAttributes: htmlAttributes);
         }
+
+        /// <summary>
+        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form, the
+        /// default route will forward the request to an action method.
+        /// </summary>
+        /// <param name="htmlHelper">The <see cref="IHtmlHelper"/> instance this method extends.</param>
+        /// <param name="routeValues">
+        /// An <see cref="object"/> that contains the parameters for a route. The parameters are retrieved through
+        /// reflection by examining the properties of the <see cref="object"/>. This <see cref="object"/> is typically
+        /// created using <see cref="object"/> initializer syntax. Alternatively, an
+        /// <see cref="System.Collections.Generic.IDictionary{string, object}"/> instance containing the route
+        /// parameters.
+        /// </param>
+        /// <returns>
+        /// An <see cref="MvcForm"/> instance which renders the &lt;/form&gt; end tag when disposed.
+        /// </returns>
+        /// <remarks>
+        /// In this context, "renders" means the method writes its output using <see cref="ViewContext.Writer"/>.
+        /// </remarks>
+        public static MvcForm BeginRouteForm([NotNull] this IHtmlHelper htmlHelper, object routeValues)
+        {
+            return htmlHelper.BeginRouteForm(
+                routeName: null,
+                routeValues: routeValues,
+                method: FormMethod.Post,
+                htmlAttributes: null);
+        }
+
+        /// <summary>
+        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form, the
+        /// <paramref name="routeName"/> route will forward the request to an action method.
+        /// </summary>
+        /// <param name="htmlHelper">The <see cref="IHtmlHelper"/> instance this method extends.</param>
+        /// <param name="routeName">The name of the route.</param>
+        /// <returns>
+        /// An <see cref="MvcForm"/> instance which renders the &lt;/form&gt; end tag when disposed.
+        /// </returns>
+        /// <remarks>
+        /// In this context, "renders" means the method writes its output using <see cref="ViewContext.Writer"/>.
+        /// </remarks>
+        public static MvcForm BeginRouteForm([NotNull] this IHtmlHelper htmlHelper, string routeName)
+        {
+            return htmlHelper.BeginRouteForm(
+                routeName,
+                routeValues: null,
+                method: FormMethod.Post,
+                htmlAttributes: null);
+        }
+
+        /// <summary>
+        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form, the
+        /// <paramref name="routeName"/> route will forward the request to an action method.
+        /// </summary>
+        /// <param name="htmlHelper">The <see cref="IHtmlHelper"/> instance this method extends.</param>
+        /// <param name="routeName">The name of the route.</param>
+        /// <param name="routeValues">
+        /// An <see cref="object"/> that contains the parameters for a route. The parameters are retrieved through
+        /// reflection by examining the properties of the <see cref="object"/>. This <see cref="object"/> is typically
+        /// created using <see cref="object"/> initializer syntax. Alternatively, an
+        /// <see cref="System.Collections.Generic.IDictionary{string, object}"/> instance containing the route
+        /// parameters.
+        /// </param>
+        /// <returns>
+        /// An <see cref="MvcForm"/> instance which renders the &lt;/form&gt; end tag when disposed.
+        /// </returns>
+        /// <remarks>
+        /// In this context, "renders" means the method writes its output using <see cref="ViewContext.Writer"/>.
+        /// </remarks>
+        public static MvcForm BeginRouteForm(
+            [NotNull] this IHtmlHelper htmlHelper,
+            string routeName,
+            object routeValues)
+        {
+            return htmlHelper.BeginRouteForm(routeName, routeValues, FormMethod.Post, htmlAttributes: null);
+        }
+
+        /// <summary>
+        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form, the
+        /// <paramref name="routeName"/> route will forward the request to an action method.
+        /// </summary>
+        /// <param name="htmlHelper">The <see cref="IHtmlHelper"/> instance this method extends.</param>
+        /// <param name="routeName">The name of the route.</param>
+        /// <param name="method">The HTTP method for processing the form, either GET or POST.</param>
+        /// <returns>
+        /// An <see cref="MvcForm"/> instance which renders the &lt;/form&gt; end tag when disposed.
+        /// </returns>
+        /// <remarks>
+        /// In this context, "renders" means the method writes its output using <see cref="ViewContext.Writer"/>.
+        /// </remarks>
+        public static MvcForm BeginRouteForm(
+            [NotNull] this IHtmlHelper htmlHelper,
+            string routeName,
+            FormMethod method)
+        {
+            return htmlHelper.BeginRouteForm(routeName, routeValues: null, method: method, htmlAttributes: null);
+        }
+
+        /// <summary>
+        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form, the
+        /// <paramref name="routeName"/> route will forward the request to an action method.
+        /// </summary>
+        /// <param name="htmlHelper">The <see cref="IHtmlHelper"/> instance this method extends.</param>
+        /// <param name="routeName">The name of the route.</param>
+        /// <param name="routeValues">
+        /// An <see cref="object"/> that contains the parameters for a route. The parameters are retrieved through
+        /// reflection by examining the properties of the <see cref="object"/>. This <see cref="object"/> is typically
+        /// created using <see cref="object"/> initializer syntax. Alternatively, an
+        /// <see cref="System.Collections.Generic.IDictionary{string, object}"/> instance containing the route
+        /// parameters.
+        /// </param>
+        /// <param name="method">The HTTP method for processing the form, either GET or POST.</param>
+        /// <returns>
+        /// An <see cref="MvcForm"/> instance which renders the &lt;/form&gt; end tag when disposed.
+        /// </returns>
+        /// <remarks>
+        /// In this context, "renders" means the method writes its output using <see cref="ViewContext.Writer"/>.
+        /// </remarks>
+        public static MvcForm BeginRouteForm(
+            [NotNull] this IHtmlHelper htmlHelper,
+            string routeName,
+            object routeValues,
+            FormMethod method)
+        {
+            return htmlHelper.BeginRouteForm(routeName, routeValues, method, htmlAttributes: null);
+        }
+
+        /// <summary>
+        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form, the
+        /// <paramref name="routeName"/> route will forward the request to an action method.
+        /// </summary>
+        /// <param name="htmlHelper">The <see cref="IHtmlHelper"/> instance this method extends.</param>
+        /// <param name="routeName">The name of the route.</param>
+        /// <param name="method">The HTTP method for processing the form, either GET or POST.</param>
+        /// <param name="htmlAttributes">
+        /// An <see cref="object"/> that contains the HTML attributes for the element. Alternatively, an
+        /// <see cref="System.Collections.Generic.IDictionary{string, object}"/> instance containing the HTML
+        /// attributes.
+        /// </param>
+        /// <returns>
+        /// An <see cref="MvcForm"/> instance which renders the &lt;/form&gt; end tag when disposed.
+        /// </returns>
+        /// <remarks>
+        /// In this context, "renders" means the method writes its output using <see cref="ViewContext.Writer"/>.
+        /// </remarks>
+        public static MvcForm BeginRouteForm(
+            [NotNull] this IHtmlHelper htmlHelper,
+            string routeName,
+            FormMethod method,
+            object htmlAttributes)
+        {
+            return htmlHelper.BeginRouteForm(
+                routeName,
+                routeValues: null,
+                method: method,
+                htmlAttributes: htmlAttributes);
+        }
     }
 }

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

@@ -82,8 +82,8 @@ namespace Microsoft.AspNet.Mvc.Rendering
         HtmlString AntiForgeryToken();
 
         /// <summary>
-        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form,
+        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form, the
-        /// the request will be processed by an action method.
+        /// <paramref name="actionName"/> method will process the request.
         /// </summary>
         /// <param name="actionName">The name of the action method.</param>
         /// <param name="controllerName">The name of the controller.</param>
@@ -111,6 +111,34 @@ namespace Microsoft.AspNet.Mvc.Rendering
             FormMethod method,
             object htmlAttributes);
 
+        /// <summary>
+        /// Renders a &lt;form&gt; start tag to the response. When the user submits the form, the
+        /// <paramref name="routeName"/> route will forward the request to an action method.
+        /// </summary>
+        /// <param name="routeName">The name of the route.</param>
+        /// <param name="routeValues">
+        /// An <see cref="object"/> that contains the parameters for a route. The parameters are retrieved through
+        /// reflection by examining the properties of the <see cref="object"/>. This <see cref="object"/> is typically
+        /// created using <see cref="object"/> initializer syntax. Alternatively, an
+        /// <see cref="IDictionary{string, object}"/> instance containing the route parameters.
+        /// </param>
+        /// <param name="method">The HTTP method for processing the form, either GET or POST.</param>
+        /// <param name="htmlAttributes">
+        /// An <see cref="object"/> that contains the HTML attributes for the element. Alternatively, an
+        /// <see cref="IDictionary{string, object}"/> instance containing the HTML attributes.
+        /// </param>
+        /// <returns>
+        /// An <see cref="MvcForm"/> instance which renders the &lt;/form&gt; end tag when disposed.
+        /// </returns>
+        /// <remarks>
+        /// In this context, "renders" means the method writes its output using <see cref="ViewContext.Writer"/>.
+        /// </remarks>
+        MvcForm BeginRouteForm(
+            string routeName,
+            object routeValues,
+            FormMethod method,
+            object htmlAttributes);
+
         /// <summary>
         /// Returns an &lt;input&gt; element of type "checkbox" with value "true" and an &lt;input&gt; element of type
         /// "hidden" with value "false".

test/Microsoft.AspNet.Mvc.Core.Test/Rendering/DefaultEditorTemplatesTests.cs

@@ -758,6 +758,15 @@ Environment.NewLine;
                 throw new NotImplementedException();
             }
 
+            public MvcForm BeginRouteForm(
+                string routeName,
+                object routeValues,
+                FormMethod method,
+                object htmlAttributes)
+            {
+                throw new NotImplementedException();
+            }
+
             public HtmlString CheckBox(string name, bool? isChecked, object htmlAttributes)
             {
                 return new HtmlString("__CheckBox__");