Razor View Engine that supports view "versioning" determined from RouteData

VersionedRazorViewEngine.cs

using System.Web.Mvc;

namespace VersionedViewEngineBench.Helpers
{
    /* Add to Global.asax.cs
    
    // Clears all previously registered view engines.
    ViewEngines.Engines.Clear();
    // Registers our Razor C# specific view engine.
    ViewEngines.Engines.Add(new VersionedRazorViewEngine());
    
    //Versioning
    routes.MapRoute(
       name: "Versioning",
       url: "v{version}/{controller}/{action}/{id}",
       defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional },
       constraints: new { version = @"\d" });
    */
    
    public class VersionedRazorViewEngine : RazorViewEngine
    {
        public string VersionKey { get { return "version"; } }

        public VersionedRazorViewEngine()
        {
            AreaViewLocationFormats = new[]
            {
                "~/Areas/{2}/Views/{1}/{0}%1%.cshtml", 
                //"~/Areas/{2}/Views/{1}/{0}%1%.vbhtml", 
                "~/Areas/{2}/Views/Shared/{0}%1%.cshtml", 
                //"~/Areas/{2}/Views/Shared/{0}%1%.vbhtml"
            };

            AreaMasterLocationFormats = new string[]
            {
                "~/Areas/{2}/Views/{1}/{0}%1%.cshtml", 
                //"~/Areas/{2}/Views/{1}/{0}%1%.vbhtml", 
                "~/Areas/{2}/Views/Shared/{0}%1%.cshtml", 
                //"~/Areas/{2}/Views/Shared/{0}%1%.vbhtml"
            };

            AreaPartialViewLocationFormats = new string[]
            {
                "~/Areas/{2}/Views/{1}/{0}%1%.cshtml", 
                //"~/Areas/{2}/Views/{1}/{0}%1%.vbhtml", 
                "~/Areas/{2}/Views/Shared/{0}%1%.cshtml", 
                //"~/Areas/{2}/Views/Shared/{0}%1%.vbhtml"
            };

            ViewLocationFormats = new[]
            {
                "~/Views/{1}/{0}%1%.cshtml", 
                //"~/Views/{1}/{0}%1%.vbhtml", 
                "~/Views/Shared/{0}%1%.cshtml", 
                //"~/Views/Shared/{0}%1%.vbhtml"
            };

            MasterLocationFormats = new[]
            {
                "~/Views/{1}/{0}%1%.cshtml", 
                //"~/Views/{1}/{0}%1%.vbhtml", 
                "~/Views/Shared/{0}%1%.cshtml", 
                //"~/Views/Shared/{0}%1%.vbhtml"
            };

            PartialViewLocationFormats = new[]
            {
                "~/Views/{1}/{0}%1%.cshtml", 
                //"~/Views/{1}/{0}%1%.vbhtml", 
                "~/Views/Shared/{0}%1%.cshtml", 
                //"~/Views/Shared/{0}%1%.vbhtml"
            };
        }

        protected override IView CreatePartialView(ControllerContext controllerContext, string partialPath)
        {
            return base.CreatePartialView(controllerContext, GetViewPath(controllerContext, partialPath));
        }

        protected override IView CreateView(ControllerContext controllerContext, string viewPath, string masterPath)
        {
            return base.CreateView(
                controllerContext, GetViewPath(controllerContext, viewPath), GetViewPath(controllerContext, masterPath));
        }

        protected override bool FileExists(ControllerContext controllerContext, string virtualPath)
        {
            return base.FileExists(controllerContext, GetViewPath(controllerContext, virtualPath));
        }


        private string GetViewPath(ControllerContext controllerContext, string virtualPath)
        {
            if (string.IsNullOrEmpty(virtualPath))
            {
                return string.Empty;
            }

            int version;
            if (controllerContext.RouteData.Values.ContainsKey(VersionKey)
               && int.TryParse(controllerContext.RouteData.Values[VersionKey].ToString(), out version)
               && version > 1)
            {
                controllerContext.Controller.ViewData["version"] = version.ToString();
                return base.FileExists(controllerContext, virtualPath.Replace("%1%", ".v" + version))
                       ? virtualPath.Replace("%1%", ".v" + version)
                       : virtualPath.Replace("%1%", string.Empty);
            }
            else
            {
                controllerContext.Controller.ViewData["version"] = string.Empty;
                return virtualPath.Replace("%1%", string.Empty);
            }
        }
    }
}