如何避免ViewBag(或ViewData)支持模型？

Question

这是一个非常简单的例子,但它足以证明我的问题.我需要将模型传递给我的用户将更新的视图,但视图还需要一些其他数据来创建下拉列表或提供其他信息.

根据我下面的代码,我想避免使用ViewBag/ViewData,所以我会以某种方式将(QuestionList以及PasswordLength多余的示例场景)组合到ChangeSecurityQuestionModel或创建新的ViewModel或其他对象？

[Authorize]
public ActionResult ChangeSecurityQuestion() {
  var user = Membership.GetUser();
  if (user != null) {
    var model = new ChangeSecurityQuestionModel() {
      PasswordQuestion = user.PasswordQuestion
    };
    ViewBag.QuestionList = new SelectList(membershipRepository.GetSecurityQuestionList(), "Question", "Question");
    ViewBag.PasswordLength = MembershipService.MinPasswordLength;
    return View(model);
  }

  // user not found
  return RedirectToAction("Index");
}

[Authorize]
[HttpPost]
public ActionResult ChangeSecurityQuestion(ChangeSecurityQuestionModel model) {
  if (ModelState.IsValid) {
    var user = Membership.GetUser();
    if (user != null) {
      if (user.ChangePasswordQuestionAndAnswer(model.Password, model.PasswordQuestion, model.PasswordAnswer)) {
        return View("ChangeQuestionSuccess");
      } else {
        ModelState.AddModelError("", "The password is incorrect.");
      }
    }
  }

  // If we got this far, something failed, redisplay form
  ViewBag.QuestionList = new SelectList(membershipRepository.GetSecurityQuestionList(), "Question", "Question");
  ViewBag.PasswordLength = MembershipService.MinPasswordLength;
  return View(model);
}

Answer 1

为什么不将QuestionList和PasswordLength放在ChangeSecurityQuestionModel中

var model = new ChangeSecurityQuestionModel() {
      PasswordQuestion = user.PasswordQuestion,
      QuestionList = new SelectList(membershipRepository.GetSecurityQuestionList(), "Question", "Question"),
      PasswordLength = MembershipService.MinPasswordLength;
    };