Question

Simple situation

One object User have many UserGroups.

I want to implement on mvc3 form editing or creating action to select UserGroups from drop down.

Controller:

private List<User> GetAllUsers()
{
    List<User> users;
    users = find all users to List...
    return users;
}

public ActionResult Edit(Guid Id)
{
   ViewBag.UserGroups = new SelectList(GetAllUsers(), "UserId", "Name");
   return View();
}

View:

<div class="editor-label">
    @Html.LabelFor(model => model.UserGroupId, "UserGroupId")
</div>
<div class="editor-field">
    @Html.DropDownList(WHAT TO PUT HERE ?);
    @Html.ValidationMessageFor(model => model.UserGroupId)
</div>

Answer 1

Oh please use a view model, cut that crap of a ViewBag, makes me sick every time I see it.

public class UserViewModel
{
    public int UserGroupId { get; set; }
    public IEnumerable<SelectListItem> UserGroups { get; set; }
}

and then:

public ActionResult Edit(Guid Id)
{
    var model = new UserViewModel
    {
        UserGroups = new SelectList(GetAllUsers(), "UserId", "Name")
    }
    return View(model);
}

and in the view:

@model UserViewModel
...
<div class="editor-label">
    @Html.LabelFor(model => model.UserGroupId, "UserGroupId")
    </div>
    <div class="editor-field">
        @Html.DropDownListFor(x => x.UserGroupId, Model.UserGroups);
        @Html.ValidationMessageFor(model => model.UserGroupId)
    </div>
</div>

---

but if you wanna make me sick and keep the ViewCrap:

@Html.DropDownListFor(
    x => x.UserGroupId, 
    (IEnumerable<SelectListItem>)ViewBag.UserGroups
)