ModelState.AddModelError-如何添加非属性错误？

Create(FooViewModel fvm){...}

fvm.prop2

public ActionResult Create(FooViewModel fvm){
    if (ThatComboAlreadyExists(fvm)) {
      ModelState.AddModelError(\"Model\", \"There is already one like that\");
      return View(fvm);
    }
}

ModelState.AddModelError(string key, string errorMessage);

ModelState.AddModelError(string.Empty, \"There is something wrong with Foo.\");

<%: Html.ValidationSummary(true)%>
<%: Html.ValidationMessageFor(model => model.Email) %>

ModelState.AddModelError(\"Email\", Resources.EmailInUse);

ModelState.AddModelError(\"Item1.Month\", \"This is not a valid date\");