Html.DropDownListFor将忽略ViewBag值

Question

我有以下行动方法：

 public ActionResult AdvanceSearch(string AssetTypeName) 

        {
            ViewBag.Techtypes = repository.GetAllTechnologyType().ToList();
            ViewBag.AssetID = repository.GetTechnologyTypeID(AssetTypeName);                

            return View();
        }

它将调用folloiwng视图:- //代码在这里

@Html.DropDownListFor(model =>model.AssetTypeID, ((IEnumerable<TMS.Models.TechnologyType>)ViewBag.Techtypes).Select(option => new SelectListItem {
        Text = (option == null ? "None" :option.Name), 
        Value = option.AssetTypeID.ToString(),
        Selected = (Model != null) && (option.AssetTypeID == ViewBag.AssetID)
    }), "All")

//代码在这里

但是下拉列表将始终显示默认值“All”，而不是选择与viewBag值option.AssetTypeID == ViewBag.AssetID匹配的项。明朝表示，ViewBag将有正确的价值。谁能说出什么问题了？谢谢

Answer 1

我觉得你的情况不对。尝尝这个。检查“选中”属性。

 @Html.DropDownListFor(model => model.AssetTypeID, ((IEnumerable<TechnologyType>)ViewBag.Techtypes).Select(option => new SelectListItem
           {
               Text = (option == null ? "None" : option.Name),
               Value = option.AssetTypeID.ToString(),
               Selected = (option.AssetTypeID == (int)ViewBag.AssetID)
           }), "All")