Попробуйте,
var wrapper=new HttpContextWrapper(System.Web.HttpContext.Current);
var routeData = RouteTable.Routes.GetRouteData(wrapper);
Controller con = (Controller)ControllerBuilder.Current.GetControllerFactory().CreateController(new RequestContext(wrapper, routeData), routeData.Values["controller"].ToString());
var viewData = con.ViewData;
var modelState= con.ModelState;
var form=new FormCollection();
var controllerContext = new ControllerContext(wrapper, routeData, con);
Predicate<string> propertyFilter = propertyName => new BindAttribute().IsPropertyAllowed(propertyName);
IModelBinder binder = Binders.GetBinder(typeof(FormCollection));
ModelBindingContext bindingContext = new ModelBindingContext()
{
ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(() => form, typeof(FormCollection)),
ModelName = "form",
ModelState = modelState,
PropertyFilter = propertyFilter,
ValueProvider = ValueProviderFactories.Factories.GetValueProvider(controllerContext)
};
form = (FormCollection)binder.BindModel(controllerContext, bindingContext);