如果ModelState无效，则在视图上呈现ViewModel错误

本文关键字：ViewModel 错误 视图 ModelState 无效 如果 | 更新日期: 2023-09-27 18:15:11

在我的MVC应用程序中有一个像下面这样的表单:

 @using (Html.BeginForm("Register", "User", FormMethod.Post))
    {
        <div>
            @Html.TextBoxFor(m => m.FirstName, new { placeholder = "First name", @class = "form-control", @type = "text" })
        </div>
        <div>
            @Html.TextBoxFor(m => m.LastName, new { placeholder = "Last name", @class = "form-control", @type = "text" })
        </div>
        <div>
            @Html.TextBoxFor(m => m.Email, new { placeholder = "Email", @class = "form-control", @type = "email" })
        </div>
        <div>
            @Html.TextBoxFor(m => m.Password, new { placeholder = "Password", @class = "form-control", @type = "password" })
        </div>
        <div>
            @Html.TextBoxFor(m => m.PasswordConfirm, new { placeholder = "Confirm password", @class = "form-control", @type = "password" })
        </div>
        <div>
            @Html.DropDownListFor(model => model.SelectedCountryId, Model.Countries, new { @class="select2_single form-control select2-hidden-accessible", @tabindex = "-1" })
        </div>
        <div>
            <input class="btn btn-default submit" type="submit" value="Register" />
        </div>
    }

我的ViewModel看起来像这样:

public class UserRegistrationViewModel
{
    [Required(ErrorMessage = "First name is required!")]
    public string FirstName { get; set; }
    [Required(ErrorMessage = "Last name is required!")]
    public string LastName { get; set; }
    [Required(ErrorMessage = "Email name is required!")]
    public string Email { get; set; }
    [Required(ErrorMessage = "Password name is required!")]
    public string Password { get; set; }
    [Required(ErrorMessage = "Password confirmation name is required!")]
    public string PasswordConfirm { get; set; }
    public int SelectedCountryId { get; set; }
    [Required(ErrorMessage = "Country needs to be selected!")]
    public SelectList Countries { get; set; }
}

这是我的两个动作:

public ActionResult Index()
{
    var model = new UserRegistrationViewModel();
    var countries = Connection.ctx.Countries.OrderBy(x => x.CountryName).ToList();
    model.Countries = new SelectList(countries, "CountryId", "CountryName");
    return View(model);
}
[HttpPost]
public ActionResult Register(UserRegistrationViewModel model)
{ 
    if (ModelState.IsValid)
    {
        var user = new Users();
        user.FirstName = model.FirstName;
        user.LastName =model.LastName;
        user.Email = model.Email;
        user.PasswordSalt = Helpers.PasswordHelper.CreateSalt(40);
        user.PasswordHash = Helpers.PasswordHelper.CreatePasswordHash(model.Password, user.PasswordSalt);
        user.CountryId = Convert.ToInt32(model.SelectedCountryId);
        user.Active = true;
        Connection.ctx.Users.Add(user);
        Connection.ctx.SaveChanges();
        var role = new UserRoles();
        role.RoleId = 2;
        role.UserId = user.UserId;
        role.Active = true;
        user.UserRoles.Add(role);
        Connection.ctx.SaveChanges();
        return RedirectToAction("Index");
    }
    return null;
}

现在我的问题是，如果模型状态无效，我该怎么办?显示错误信息，我已经设置在我的ViewModel)??

我只是做' return View();还是? ?

我现在需要在我的视图中呈现这些消息

如果ModelState无效，则在视图上呈现ViewModel错误

每当我收到提交的无效表单时，我返回View()以纠正问题。将用户带到一个错误页面，他们必须返回表单并重新开始，这会让用户感到沮丧。把无效的表格还给他们，并告诉他们哪些地方需要修改。

现在，需要校正的可以从ViewBag()中读取。或者你可以在你的Model内部有一些属性，将为用户保存错误信息，并在它们不为空时显示它们。

在无效模型状态的情况下，您可以只返回当前视图，并将模型作为参数:

if (!ModelState.IsValid)
{
    return View(model);
}
编辑:在你的html中，添加html元素来显示验证消息: 
@Html.ValidationMessageFor(model => model.FirstName)
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