模型验证是检查引用的模型对象中的必填字段，当只需要一个键时

Question

我正在为学生模型创建一个编辑表单：

public class Student
{
    [Key]
    public virtual int ID { get; set; }

    [Required]
    public virtual StudentGuardian Guardian { get; set; }
}

这个学生里面有一个StudentGuardian实例，StudentGuardian有关于姓名，性别等的验证属性

public class StudentGuardian
{
    [Key]
    public virtual int ID { get; set; }

    [Required]
    public virtual string Name { get; set; }

    [Required]
    public virtual string MobilePhone { get; set; }

    [Required]
    public virtual Sex Sex { get; set; }
}

但是在学生编辑表格中，我只对GuardianId感兴趣。 关键是在创建编辑表单并在表单中创建类似的内容时：

@Html.DropDownListFor(x => x.Student.Guardian.ID, <GUARDIANS_LIST>)

由于Student模型需要Guardian对象，因此MVC验证要求我输入Guardian.Name和Guardian.MobilePhone等，

我怎样才能将验证强制为Guardian.Id只有整个对象？

Answer 1

将StudentGuardian保留在Student的唯一想法是在Student和StudentGuardian类之间创建StudentGuardian关系，而不是将数据呈现给view 。 通过您的方法，您不仅会在编辑学生实体时以及在创建学生实体时遇到错误。 尝试使用其他人推荐的视图模型。 以下只是帮助您更好地理解的尝试。

public class StudentViewModel
{
        public int StudentId { get; set; }

        public string Name { get; set; }

        //..other member variables..

        [Display(Name="Guardian"]
        public int GuardianId { get; set; }
        public virtual IEnumerable<StudentGuardian> Guardians { get; set; }

}

然后在您的Controller的Edit操作中

    [HttpGet]
    public ActionResult Edit(int id = 0)
    {
        Student student = db.Students.Find(id);
        var model = new StudentViewModel();
        model.Name = student.Name;
        model.Guardians = db.Guardians.ToList();

        //or if using repository then call the method that fetches
        //.. you the list of objects 
        //..and bind it to the StudentViewModel instance created.

        //Other Properties you need..fetch and assign them here..
        //model.StudentId= student.Id; ... etc


        if (student == null)
        {
            return HttpNotFound();
        }
        return View(model); // return the viewModel instance.
    }

使用StudentViewModel绑定您的Edit View 。

@model MvcApplication.Models.ViewModels.StudentViewModel
@{
    ViewBag.Title = "Edit";
}

<h2>Edit</h2>

@using (Html.BeginForm()) {
    @Html.ValidationSummary(true)

    <fieldset>
        <legend>Student</legend>

        @Html.HiddenFor(model => model.StudentId)

        <div class="editor-label">
            @Html.LabelFor(model => model.Name)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.Name)
            @Html.ValidationMessageFor(model => model.Name)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.GuardianId)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.GuardianId)
            @Html.DropDownListFor(model => model.GuardianId, new SelectList(Model.Guardians, "GuardianId", "GuardianName"),"Select")
        </div>


        <p>
            <input type="submit" value="Save" />
        </p>
    </fieldset>
}

<div>
    @Html.ActionLink("Back to List", "Index")
</div>

@section Scripts {
    @Scripts.Render("~/bundles/jqueryval")
}

在StudentViewModel类的引用上接收数据

   [HttpPost]
   public ActionResult Edit(StudentViewModel model)
    {
          //..do whatever..Save to Database or something else..
    }

尝试谷歌搜索ViewModels，您将获得大量资源。