我有2个班级: 用户和作用

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; }
}

我设立了阅读/标准实体的用户主计长,在制作方法时,我设立了“观点”。 作用清单

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

目的是:

<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>

In create view with HttpPost attribute, when user choose one role, and submit, I can t get a value of role. Anyone who know the way to add role into user by select dropdownlist? I means, when I drop down list role and select item in there, and submit, I add one user row into table Thank you