如何在C# MVC中过滤下拉列表

// 数据模型
public class SelectListItemModel
{
    public int Id { get; set; }
    public string Name { get; set; }
}

// 控制器
public class MyController : Controller
{
    public ActionResult Index()
    {
        // 获取数据源（这里使用了一个简单的静态数据源）
        List<SelectListItemModel> data = new List<SelectListItemModel>
        {
            new SelectListItemModel { Id = 1, Name = "Option 1" },
            new SelectListItemModel { Id = 2, Name = "Option 2" },
            new SelectListItemModel { Id = 3, Name = "Option 3" },
            new SelectListItemModel { Id = 4, Name = "Option 4" }
        };

        // 过滤数据源
        var filteredData = data.Where(item => item.Id % 2 == 0).ToList();

        // 传递数据到视图
        ViewBag.Options = new SelectList(filteredData, "Id", "Name");

        return View();
    }
}

// 视图
@{
    ViewBag.Title = "Index";
}

<h2>Filtered Dropdown List</h2>

@Html.DropDownList("SelectedOption", ViewBag.Options as SelectList, "Select an option")