在 mvc 中创建时与下拉列表中的对象进行交互

Question

我有 2 个类：用户和角色，用户有一个角色

public class User : IPrincipal
{        
    public int UserId { get; set; }

    [Required]
    [Display(Name = "User name")]
    public string Username { get; set; }

    [Required]
    [DataType(DataType.Password)]
    public string Password { get; set; }

    [Required]
    [DataType(DataType.EmailAddress)]
    public string Email { get; set; }

    [Display(Name = "Created date")]
    public DateTime CreatedDate { get; set; }        

    [Required]
    [Display(Name = "Password question")]
    public string PasswordQuestion { get; set; }

    [Required]
    [Display(Name = "Password anwser")]
    public string PasswordAnswer { get; set; }

    [Display(Name = "Active")]
    public bool IsApproved { get; set; }

    [Display(Name = "Last login date")]
    public DateTime LastLoginDate { get; set; }

    [Display(Name = "Last password changed date")]
    public DateTime LastPasswordChangedDate { get; set; }

    [Display(Name = "Last activity date")]
    public DateTime LastActivityDate { get; set; }

    public virtual Role Role { get; set; }

    public virtual IIdentity Identity { get; set; }
    public virtual bool IsInRole(string role)
    {
        if (Role.Name.ToLower() == role.ToLower())
        {
            return true;
        }
        return false;
    }
} 

public class Role
{
    public int RoleId { get; set; }

    [Required]
    [Display(Name = "Role name")]
    public string Name { get; set; }
}

我创建了带有读/写实体的 UserController，在 Create 方法中，我创建了 ViewBag.Role 包含角色列表

public ActionResult Create()
{
    ViewBag.Role = new SelectList(db.Roles, "RoleId", "Name");
    return View();
} 

在创建视图中：

<div class="editor-label">
    @Html.LabelFor(model => model.Role)
</div>
<div class="editor-field">
    @Html.DropDownList("Role")
    @Html.ValidationMessageFor(model => model.Role.RoleId) @* I don't know this is correct? *@
</div>

在带有 HttpPost 属性的创建视图中，当用户选择一个角色，然后提交，我无法获得角色的值。 有人知道如何通过选择下拉列表将角色添加到用户中吗？我的意思是，当我下拉列表角色并选择其中的项目并提交时，我将一个用户行添加到表中 谢谢

Answer 1

您可以通过将 RoleId 外键添加为 User 的属性来公开它。

那么你的观点会是这样的

<div class="editor-field">
    @Html.DropDownListFor(model => model.RoleId, (SelectList)ViewBag.Role)
    @Html.ValidationMessageFor(model => model.RoleId)
</div>