如何在循环中设置DropDownListFor中的默认值？

public ActionResult Index()
{
    // 获取需要绑定到DropDownListFor的数据
    List<string> options = new List<string> { "Option 1", "Option 2", "Option 3" };

    // 设置默认值
    string defaultValue = "Option 2";

    // 将数据和默认值传递给视图
    ViewBag.Options = options;
    ViewBag.DefaultValue = defaultValue;

    return View();
}

@{
    // 获取数据和默认值
    List<string> options = ViewBag.Options;
    string defaultValue = ViewBag.DefaultValue;
}

@using (Html.BeginForm())
{
    @Html.DropDownListFor(model => model.SelectedOption, options.Select(option => new SelectListItem
    {
        Text = option,
        Value = option,
        Selected = option == defaultValue // 设置默认值
    }), "Please select an option")

    <input type="submit" value="Submit" />
}