c# - ASP MVC4 的下拉列表

Question

我收到此错误“CS1928:

'System.Web.Mvc.HtmlHelper' does not contain a definition for 'DropDownListFor' and the best extension method overload 'System.Web.Mvc.Html.SelectExtensions.DropDownListFor(System.Web.Mvc.HtmlHelper, System.Linq.Expressions.Expression>, System.Collections.Generic.IEnumerable)' has some invalid arguments"

我的 Controller 看起来像这样

    public class IndexController : Controller
{
       public ActionResult Index()
       {
               EpfeSelectScreen model = new EpfeSelectScreen();

               var b = (from a in dbEntitiesErste.CONFIG_APPLICATIONS
                               orderby a.APPLICATION_ID
                               select new EPFE.CustomDataObjects.CustomObjects
                               {
                                   Text = a.APPLICATION_NAME,
                                   Value = a.APPLICATION_ID
                               });

               model.Application = b.OrderBy(x => x.Text).ToList();

               return View(model); 




       }
}

我的模型是这样的

    public class EpfeSelectScreen
{ 
    public string Search { get; set; }
    public string selectedApplication { get; set; }
    public List<SelectListItem> Country { get; set; }
    public List<CustomObjects> Application { get; set; }
    public List<SelectListItem> MetaData { get; set; }
    public List<SelectListItem> References { get; set; }
    public List<SelectListItem> ReferencedBy { get; set; }
    public List<SelectListItem> TreeView { get; set; }       

    public EpfeSelectScreen()
    {
        Country = new List<SelectListItem>();
        Application = new List<CustomObjects>();           
        References = new List<SelectListItem>();
        ReferencedBy = new List<SelectListItem>();
        TreeView = new List<SelectListItem>();        
    }
}

我的 CustomObjects 是这个

    public class CustomObjects
{
    public string Text { get; set; }
    public short Value { get; set; }
}

我的 model.Application 中有一条记录，但是当该数据传递到我的 View 时，我得到了那个错误。

我的 View 看起来像这样

@model EPFE.Controllers.EpfeSelectScreen
@Html.DropDownListFor(m => m.selectedApplication, Model.Application) 

如何解决这个问题？我究竟做错了什么？当我尝试使用 ListBoxFor 时出现同样的错误。

Answer 1

DropDownListFor 在传递 List 时将 SelectList 作为第二个参数。

你可以有类似下面的东西:

@Html.DropDownListFor(m => m.selectedApplication, 
                     new SelectList(Model.Application,"Value","Text"))