is it alright to use this in a PRG scenario in asp.net mvc? or totally not done?

gistfile1.cs

    public class SetTempDataWhenModelStateInvalidAttribute : ActionFilterAttribute
    {
        public override void OnActionExecuted(ActionExecutedContext filterContext)
        {
            base.OnActionExecuted(filterContext);
            if (!filterContext.Controller.ViewData.ModelState.IsValid)
            {
                filterContext.Controller.TempData["ModelState"] = filterContext.Controller.ViewData.ModelState;
            }
        }
    }


    public class RestoreModelStateFromTempDataAttribute : ActionFilterAttribute
    {
        public override void OnActionExecuting(ActionExecutingContext filterContext)
        {
            base.OnActionExecuting(filterContext);
            if (filterContext.Controller.TempData.ContainsKey("ModelState"))
            {
                filterContext.Controller.ViewData.ModelState.Merge((ModelStateDictionary)filterContext.Controller.TempData["ModelState"]);
            }
        }
    }