asp.net-mvc – MVC DropDownList SelectedValue不正确显示

var statuses  = new SELEctList(db.orderstatuses,"ID","Name",order.Status.ID.ToString());
ViewBag.Statuses = statuses;
return View(vm);

<div class="display-label">
   Order Status</div>
<div class="editor-field">
   @Html.DropDownListFor(model => model.StatusID,(SELEctList)ViewBag.Statuses)
   @Html.ValidationmessageFor(model => model.StatusID)
</div>

SELEctList构造函数(希望能够传递所选值id)的最后一个参数被忽略，因为DropDownListFor Helper使用您作为第一个参数传递的lambda表达式，并使用特定属性的值。

所以这是丑陋的方法：

模型：

public class Mymodel
{
    public int StatusID { get; set; }
}

控制器：

public class HomeController : Controller
{
    public ActionResult Index()
    {
        // TODO: obviously this comes from your DB,// but I hate showing code on SO that people are
        // not able to compile and play with because it has 
        // gazzilion of external dependencies
        var statuses = new SELEctList(
            new[] 
            {
                new { ID = 1,Name = "status 1" },new { ID = 2,Name = "status 2" },new { ID = 3,Name = "status 3" },new { ID = 4,Name = "status 4" },},"Name"
        );
        ViewBag.Statuses = statuses;

        var model = new Mymodel();
        model.StatusID = 3; // preSELEct the element with ID=3 in the list
        return View(model);
    }
}

视图：

@model Mymodel
...    
@Html.DropDownListFor(model => model.StatusID,(SELEctList)ViewBag.Statuses)

这是正确的方式，使用真实的视图模型：

模型

public class Mymodel
{
    public int StatusID { get; set; }
    public IEnumerable<SELEctListItem> Statuses { get; set; }
}

控制器：

public class HomeController : Controller
{
    public ActionResult Index()
    {
        // TODO: obviously this comes from your DB,"Name"
        );
        var model = new Mymodel();
        model.Statuses = statuses;
        model.StatusID = 3; // preSELEct the element with ID=3 in the list
        return View(model);
    }
}

视图：

@model Mymodel
...    
@Html.DropDownListFor(model => model.StatusID,Model.Statuses)