如何给DropDownListFor设置默认值

1、直接赋值：

@Html.DropDownListFor(o => o.ParentId, ViewBag.root as IEnumerable<SelectListItem>,"默认值")

2、在初始化时赋值：

View层：

@Html.DropDownListFor(o => o.ParentId, ViewBag.root as IEnumerable<SelectListItem>)

Controller层：

var parent = _dictionaryService.Where(o => o.IsDeleted == false && o.DisLevel == 1).ToList().Select(o => new SelectListItem(){Text = o.Name.ToString(),Value = o.Id.ToString()});ViewBag.root = parent;DictionaryViewModel viewModel = new DictionaryViewModel();viewModel.ParentId = id;string disOrder = "";disOrder = LoadDetailOrderNumber(id);viewModel.DisOrder = disOrder.AsInt();return View(viewModel);