ASP.NET MVC:将自定义属性放入选择列表中的选项标记中

public class CustomAttribute
{
    public int Value { get; set; }
    public string Text { get; set; }
    public bool Selected { get; set; }
}

public ActionResult Index()
{
    List<CustomAttribute> attributes = new List<CustomAttribute>
    {
        new CustomAttribute { Value = 1, Text = "Option 1", Selected = true },
        new CustomAttribute { Value = 2, Text = "Option 2", Selected = false },
        new CustomAttribute { Value = 3, Text = "Option 3", Selected = false },
    };

    return View(attributes);
}

@model List<CustomAttribute>

@{
    ViewBag.Title = "Index";
}

@Html.DropDownListFor(m => m.FirstOrDefault(a => a.Selected).Value,
    new SelectList(Model, "Value", "Text", Model.FirstOrDefault(a => a.Selected).Value),
    "Select an option",
    new { id = "myDropDown" }
)