System.Web.Mvc.T4Extensions.AddRouteValues C# (CSharp) Method

        public static ActionResult AddRouteValues(this ActionResult result, RouteValueDictionary routeValues) {
            RouteValueDictionary currentRouteValues = result.GetRouteValueDictionary();

            // Add all the extra values
            foreach (var pair in routeValues) {
                currentRouteValues.Add(pair.Key, pair.Value);
            }

            return result;
        }

 public static TActionResult AddRouteValues <TActionResult>(this TActionResult result, NameValueCollection nameValueCollection) where TActionResult : ActionResult
 {
     return((TActionResult)T4Extensions.AddRouteValues(result, nameValueCollection));
 }