Question

I have an entity, lets say Person:

class Person
{
    id Id { get; set; }
    string Name { get; set; }
    int RoleId { get; set; }
}

This RoleId property corresponds to a role selected from a list of available Roles. I pass this list of roles to the view using the ViewData object:

List<SelectListItem> roles = new List<SelectListItem>()
{
    new SelectListItem(){ Text = "User", Value = "0"},
    new SelectListItem(){ Text = "Admin", Value = "1"}
};
ViewData["roles"] = roles;

(Note I use strings as values here as it doesn’t let me use integers?)

My View (it’s an “add” view, to create a new Person) inherits from the Person entity. I am unsure how to setup the dropdown list in the view so that the value of the selected item in the list gets set as the RoleId property value in the Person object that is sent back to the Controller (for the HttpPost method).

Answer 1

<%= Html.DropDownList(
    "RoleId", 
    new SelectList(ViewData["roles"] as IEnumerable<SelectListItem>, "Value", "Text")
) %>

This being said it is not a code that I would recommend. Everytime I see someone using ViewData my temperature raises.

I would use view models:

public class PersonViewModel
{
    public string Id { get; set; }
    public string Name { get; set; }

    public string RoleId { get; set; }
    public IEnumerable<SelectListItem> Roles { get; set; }
}

and then in your controller:

public ActionResult Index()
{
    var model = new PersonViewModel
    {
        Roles = new[]
        {
            new SelectListItem { Text = "User", Value = "0" },
            new SelectListItem { Text = "Admin", Value = "1" }
        }
    };
    return View(model);
}

and in your strongly typed view:

<%= Html.DropDownListFor(
    x => x.RoleId, 
    new SelectList(Model.Roles, "Value", "Text")
) %>