如何使用Html.DropDownList为默认选项设置值

public ActionResult Index()
{
    List<SelectListItem> items = new List<SelectListItem>();
    items.Add(new SelectListItem { Text = "Option 1", Value = "1" });
    items.Add(new SelectListItem { Text = "Option 2", Value = "2" });
    items.Add(new SelectListItem { Text = "Option 3", Value = "3" });

    ViewBag.Options = items;
    return View();
}

@Html.DropDownList("SelectedOption", (IEnumerable<SelectListItem>)ViewBag.Options, "请选择一个选项", new { @class = "form-control" })

public ActionResult Index()
{
    List<SelectListItem> items = new List<SelectListItem>();
    items.Add(new SelectListItem { Text = "Option 1", Value = "1" });
    items.Add(new SelectListItem { Text = "Option 2", Value = "2" });
    items.Add(new SelectListItem { Text = "Option 3", Value = "3" });

    // 设置默认选项的值
    items.Where(x => x.Value == "2").FirstOrDefault().Selected = true;

    ViewBag.Options = items;
    return View();
}