MVC 2:如何使用Html.DropDownListFor？

public class MyModel
{
    public string SelectedValue { get; set; }
    public List<SelectListItem> DropDownListItems { get; set; }
}

public ActionResult MyAction()
{
    var model = new MyModel
    {
        DropDownListItems = new List<SelectListItem>
        {
            new SelectListItem { Text = "Option 1", Value = "1" },
            new SelectListItem { Text = "Option 2", Value = "2" },
            new SelectListItem { Text = "Option 3", Value = "3" }
        }
    };
    return View(model);
}

@model MyModel

@Html.DropDownListFor(m => m.SelectedValue, Model.DropDownListItems, "Select an option")