如何填充Dropdown和dependent Dropdown

Question

下面是我的Dropdowns视图模型

    [Required(ErrorMessage = "Gerekli Alan")]
    [Display(Name = "İl")]
    [UIHint("DropDownList")]
    [AdditionalMetadata("DataController", "Register")]
    [AdditionalMetadata("DataAction", "Province")]
    public int? ProvinceId { get; set; }

    [Required(ErrorMessage = "Gerekli Alan")]
    [Display(Name = "İlçe")]
    [UIHint("DependentDropDownList")]
    [AdditionalMetadata("DependsOn", "ProvinceId")]
    [AdditionalMetadata("DataController", "Register")]
    [AdditionalMetadata("DataAction", "TownByProvinceId")]
    public int? TownId { get; set; }

这是控制器

[HttpPost]
    public ActionResult Province()
    {

        IQueryable<DropDownListItem> queryable = from city in Db.Provinces
                                                 orderby city.Name
                                                 select new DropDownListItem { Text = city.Name, Value = city.Id };
        return base.Json(queryable);
    }

    [HttpPost]
    public ActionResult TownByProvinceId(int ProvinceId)
    {
        IQueryable<DropDownListItem> queryable = from province in Db.Towns
                                                 where province.ProvinceId == ProvinceId
                                                 orderby province.Name
                                                 select new DropDownListItem { Text = province.Name, Value = province.Id };
        return base.Json(queryable);
    }

我正在尝试按省份列出城镇选定的ITem如何在视图中填充下拉列表？

Answer 1

使用SelectListItem可能会有更好的运气。

在ViewModel中创建List<SelectListItem>类型的属性

在调用视图之前，请填充该属性。

var model = new MyViewModel { queryable = from province in Db.Towns
                                         where province.ProvinceId == ProvinceId
                                         orderby province.Name
                                         select new SelectListItem { Text = province.Name, Value = province.Id, Selected = false }};

那么在你看来，你是这样叫它的。

@Html.DropDownListFor(m => m.ProvinceId, m.queryable)

这将为您提供一个下拉菜单，其中包含回发时存储在ProvinceId中的queryable中的所有值。