Question

我是ASP.MVC4的新手，我面临着将对象从视图传递到控制器的问题：让我从一开始就解释我的问题：我使用的类是例如：UserAndRolesModel

public class UserAndRolesModel
{
    public user User { get; set; }
    public IEnumerable<UserAndRoles> AsignedRoles { get; set; }
}

正如您可以看到类UserAndRolesModel持久存在2个对象：user和Enumerable

public class user
{
    [HiddenInput(DisplayValue=false)]
    public virtual int user_id { get; set; }

    [Required(ErrorMessage = "Please provide name")]
    [Display(Name = "Name")]
    public virtual string user_name { get; set; }

    [Display(Name = "Is active?")]
    public virtual bool user_active { get; set; }

}

public class UserAndRoles
{
    public string RoleName { get; set; }
    public bool IsAssigned { get; set; }
}

我的控制器操作很简单，它将用户分配给UserWithRoles.User并使用UserAndRoles对象创建tempList。

    public ActionResult Edit(int userid=0)
    {
      //object which will be passed to View
      UserAndRolesModel UserWithRoles = new UserAndRolesModel();

      //user
      UserWithRoles.User = repoUsers.Users.FirstOrDefault(x => x.user_id == userid);

      //roles
      IList<UserAndRoles> tempList = new List<UserAndRoles>();
      UserAndRoles temp1 = new UserAndRoles();
      temp1.RoleName="Admin";
      temp1.IsAssigned=true;
      UserAndRoles temp2 = new UserAndRoles();
      temp2.RoleName="User";
      temp2.IsAssigned=false;
      tempList.Add(temp1);
      tempList.Add(temp2);

      //assign tempList to model
      UserWithRoles.AsignedRoles = tempList;

      return View(UserWithRoles);
    )

在此阶段，我成功传递给View：

UserWithRoles.User.user_id=1;
UserWithRoles.User.user_name="UserName1";
UserWithRoles.User.user_active=true;
UserWithRoles.AsignedRoles[1].RoleName = "Admin";
UserWithRoles.AsignedRoles[1].IsAssigned = true ;
UserWithRoles.AsignedRoles[2].RoleName = "User";
UserWithRoles.AsignedRoles[2].IsAssigned = false;

我能够正确显示以上视图：

@model Models.UserAndRolesModel
@using (Html.BeginForm()) 
{
    @Html.AntiForgeryToken()
    @Html.ValidationSummary(true)

    <fieldset>
        <div class="editor-field">
            @Html.EditorFor(model => model.User.user_id)
            @Html.ValidationMessageFor(model => model.User.user_id)
        </div>


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

        <div class="editor-label">
            @Html.LabelFor(model => model.User.user_active)
        </div>
        <div class="editor-field">
            @Html.CheckBoxFor(model => model.User.user_active)
            @Html.ValidationMessageFor(model => model.User.user_active)
        </div>

        <br /> ROLES below is piece of code which makes me cry<br />
        @foreach (var item in Model.AsignedRoles)
        {
            <div class="editor-field">
            <div class="editor-field">
               @Html.LabelFor(model => item.RoleName)
               @Html.CheckBoxFor(model => item.IsAssigned)
            </div>
            </div>
        }

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

当我点击提交时，有关用户的所有数据都已正确传递，但IEnumerable AsignedRoles始终为null。这是我在帖子上的控制器方法：

[HttpPost]
public ActionResult Edit(UserAndRolesModel UserWithRoles)
    {
        if (ModelState.IsValid)
        {
                        if (UserWithRoles.AsignedRoles==null)
                            Console.WriteLine("I am still crying");
                        else
                            Console.WriteLine("Got it!");
        }
        return View(UserWithRoles);
    }

在视图中，我尝试使用其他循环，例如：

    @for (int i = 0; i < Model.AsignedRoles.Count(); i++)
    {
             <div class="editor-field">
               @Html.LabelFor(model => item[i].IsAssigned)
               @Html.CheckBoxFor(model => item[i].IsAssigned)
             </div>
    }

但上面也没有通过IEnumerable。任何人都可以帮我解决这个问题吗？我怎样才能传回包含IEnumerable的控制器UserAndRolesModel？我将非常感激。感谢您的帮助！

Answer 1

您确实需要for循环，但您尝试过的循环已引用item[i]，但item[i]不再存在。试试这个，请注意我还为HiddenFor添加了RoleName，否则将无法传回：

@for (int i = 0; i < Model.AsignedRoles.Count(); i++)
{
         <div class="editor-field">
           @Html.LabelFor(model => model.AssignedRoles[i].IsAssigned)
           @Html.CheckBoxFor(model => model.AssignedRoles[i].IsAssigned)
           @Html.HiddenFor(model => model.AssignedRoles[i].RoleName)
         </div>
}

如何将带有可枚举对象的模型传递给View？

1 个答案: