public ActionResult Index()
        {
            ViewBag.Message = "Modify this template to jump-start your ASP.NET MVC application.";

            NestedVM vm = new NestedVM();

            vm.ContactVM = new ContactVM();

            return(View("~/Views/Home/NestedModelBinding.cshtml", vm));
        }
        public ActionResult Index(NestedVM vm)
        {
            if (ModelState.IsValid)
            {
                return(Json(new { valid = ModelState.IsValid }));
            }
            else
            {
                var errorList = ModelState.ToModelStateJSON();

                return(Json(new { valid = ModelState.IsValid, validationErrors = errorList }));
            }
        }