interact objects in dropdownlist when create in mvc - asp.net-mvc-3

Question

I have 2 classes: User and Role, an user has a role
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; }
}
I created UserController with read/write entity, in Create method, I created ViewBag.Role contains list of role
public ActionResult Create()
{
ViewBag.Role = new SelectList(db.Roles, "RoleId", "Name");
return View();
}
In create view:
<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

Answer 1

You can expose the RoleId foreign key by adding it as a property of User.
Then your view would look like
<div class="editor-field">
#Html.DropDownListFor(model => model.RoleId, (SelectList)ViewBag.Role)
#Html.ValidationMessageFor(model => model.RoleId)
</div>