ASP.NET MVC组合框值加载

// 控制器中的动作方法
public ActionResult Index()
{
    List<SelectListItem> options = new List<SelectListItem>
    {
        new SelectListItem { Text = "Option 1", Value = "1" },
        new SelectListItem { Text = "Option 2", Value = "2" },
        new SelectListItem { Text = "Option 3", Value = "3" }
    };

    ViewBag.Options = options;

    return View();
}

// 视图中的代码
@Html.DropDownList("SelectedOption", (IEnumerable<SelectListItem>)ViewBag.Options, "Select an option")

// 模型类
public class MyModel
{
    public string SelectedOption { get; set; }
    public List<SelectListItem> Options { get; set; }
}

// 控制器中的动作方法
public ActionResult Index()
{
    MyModel model = new MyModel
    {
        Options = 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);
}

// 视图中的代码
@Html.DropDownListFor(model => model.SelectedOption, Model.Options, "Select an option")

// 视图模型类
public class MyViewModel
{
    public string SelectedOption { get; set; }
    public List<SelectListItem> Options { get; set; }
}

// 控制器中的动作方法
public ActionResult Index()
{
    MyViewModel viewModel = new MyViewModel
    {
        Options = 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(viewModel);
}

// 视图中的代码
@model MyViewModel

@Html.DropDownListFor(model => model.SelectedOption, Model.Options, "Select an option")