RedirectToActionAnchor.cs

using System;
using System.Web.Mvc;
using System.Web.Routing;

namespace Models
{
	public class RedirectToActionAnchor : RedirectToRouteResult
	{
		/// <summary>
		/// Gets or sets the action.
		/// </summary>
		public string Action { get; set; }

		/// <summary>
		/// Gets or sets the anchor.
		/// </summary>
		public string Anchor { get; set; }

		/// <summary>
		/// Gets or sets the controller.
		/// </summary>
		public string Controller { get; set; }

		/// <summary>
		/// Initializes a new instance of the <see cref="RedirectToActionAnchor"/> class.
		/// </summary>
		/// <param name="action">The action.</param>
		/// <param name="anchor">The anchor.</param>
		/// <param name="routeValues">The route values.</param>
		public RedirectToActionAnchor(string action, string anchor, object routeValues)
			: this(action, null, anchor, routeValues)
		{
		}

		/// <summary>
		/// Initializes a new instance of the <see cref="RedirectToActionAnchor"/> class.
		/// </summary>
		/// <param name="action">The action.</param>
		/// <param name="controller">The controller.</param>
		/// <param name="anchor">The anchor.</param>
		/// <param name="routeValues">The route values.</param>
		public RedirectToActionAnchor(string action, string controller, string anchor, object routeValues)
			: base(new RouteValueDictionary(routeValues))
		{
			if (string.IsNullOrWhiteSpace(action))
				throw new ArgumentNullException(action);

			this.Action = action;
			this.Anchor = anchor;
			this.Controller = controller;
		}

		/// <summary>
		/// Enables processing of the result of an action method by a custom type that inherits from the <see cref="T:System.Web.Mvc.ActionResult"/> class.
		/// </summary>
		/// <param name="context">The context within which the result is executed.</param>
		/// <exception cref="T:System.ArgumentNullException">The <paramref name="context"/> parameter is null.</exception>
		public override void ExecuteResult(ControllerContext context)
		{
			if (context == null)
				throw new ArgumentNullException("context");

			this.RouteValues["action"] = this.Action;

			if (!string.IsNullOrWhiteSpace(this.Controller))
				this.RouteValues["controller"] = this.Controller;

			RequestContext requestContext = new RequestContext(context.HttpContext, RouteTable.Routes.GetRouteData(context.HttpContext));
			VirtualPathData vpd = RouteTable.Routes.GetVirtualPath(requestContext, RouteName, RouteValues);

			if (vpd == null || string.IsNullOrWhiteSpace(vpd.VirtualPath))
			{
				throw new InvalidOperationException("No route matched");
			}

			string target = vpd.VirtualPath;

			if (!string.IsNullOrWhiteSpace(this.Anchor))
			{
				// Add the anchor onto the end:
				target += string.Format("#{0}", Anchor);
			}

			context.HttpContext.Response.Redirect(target, false);
		}
	}
}

This is very useful class.
I had some problems when using areas and needed to get vpd using:
VirtualPathData vpd = RouteTable.Routes.GetVirtualPathForArea(requestContext, RouteName, RouteValues);