Utility class to render MVC Partials & Actions in Webforms (or server side controls)

RenderActionPartial.spark

<viewdata ControllerName="string" />
<viewdata ActionName="string" />
<viewdata RouteValues="object" />
# Html.RenderAction(ActionName, ControllerName, RouteValues);

WebFormMVCUtil.cs

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

/* Sources:
 * 
 * http://stackoverflow.com/questions/702746/how-to-include-a-partial-view-inside-a-webform/1074061#1074061
 * http://www.blog.clicktricity.com/post/Using-MVC-RenderAction-within-a-Webform.aspx
 * */

class WebFormController : Controller { }

public static class WebFormMVCUtil
{
    static void PartialToTextWriter(TextWriter tw, string partialName, object model)
    {
        //get a wrapper for the legacy WebForm context
        HttpContextWrapper httpCtx = new HttpContextWrapper(HttpContext.Current);

        //create a mock route that points to the empty controller
        RouteData rt = new RouteData();
        rt.Values.Add("controller", "WebFormController");

        //create a controller context for the route and http context
        ControllerContext ctx = new ControllerContext(new RequestContext(httpCtx, rt), new WebFormController());

        //find the partial view using the viewengine
        IView view = ViewEngines.Engines.FindPartialView(ctx, partialName).View;

        //create a view context and assign the model
        ViewContext vctx = new ViewContext(ctx, view, new ViewDataDictionary { Model = model }, new TempDataDictionary(), tw);

        //ERROR OCCURS ON THIS LINE
        view.Render(vctx, tw);
    }

    public static void RenderPartial(string partialName, object model)
    {
        PartialToTextWriter(HttpContext.Current.Response.Output, partialName, model);
    }

    public static void RenderPartial(string partialName)
    {
        RenderPartial(partialName, null);
    }

    public static string Partial(string partialName, object model)
    {
        StringWriter sw = new StringWriter();
        PartialToTextWriter(sw, partialName, model);

        return sw.ToString();
    }

    public static string Partial(string partialName)
    {
        return Partial(partialName, null);
    }

    public static void RenderAction(string controllerName, string actionName, object routeValues)
    {
        // Requires a RenderActionPartial partial view model in the shared folder of the MVC app

        RenderPartial("RenderActionPartial", new { ControllerName = controllerName, ActionName = actionName, RouteValues = routeValues });
    }

    public static string Action(string controllerName, string actionName, object routeValues)
    {
        // Requires a RenderActionPartial partial view model in the shared folder of the MVC app

        return Partial("RenderActionPartial", new { ControllerName = controllerName, ActionName = actionName, RouteValues = routeValues });
    }
}