如何在通用存储库模式 Mvc.Net 实体框架中实现级联下拉列表？

Question

如何首先使用 EF 代码在通用存储库模式中创建级联 DropDownList，其中可用国家/地区州和城市选项中的一个注册表单从不同的数据库表中获取
公共类 ManupulationRecord : IHallBook where T : 类 我通过“HallProfile”实体模型的地方 现在如何实现City Country State级联下拉列表Adding New Record in View

namespace ModelData
{
   [Table("tblHallProfile")]
  public class HallProfile
    {


        [Key]
        public int profileId { get; set; }
        public string hallName { get; set; } 
        public string thumbnailImgPath { get; set; }
        public string hallOwnerName { get; set; }
        public string adress { get; set; }
        public string contactNumber { get; set; }
        public string emailAdress { get; set; }
        public string website { get; set; }

        public string hallCategory { get; set; }
        public string createdDate { get; set; }

        public int vehecleParking { get; set; }
        public string foodTypeVegNonVej { get; set; }
        public string decription { get; set; } 
        public decimal cost { get; set; }
        public string serviceTime { get; set; }
        public string OtherService { get; set; }
        public int publicCapacity { set; get; }
        public int cityId { get; set; }
        [ForeignKey("cityId")]
        public virtual ClsCityList cityIdt { get; set; }

        public int StateId { get; set; }
        [ForeignKey("StateId")]
        public virtual ClsStateList stateIdt { get; set; }

        public int CountryId { get; set; }
        [ForeignKey("CountryId")]
        public virtual  ClsCountryList CountryIdt { get; set; }

        public int areaId { get; set; }
        [ForeignKey("areaId")]
        public virtual ClsArea areaIdt { get; set; }
}

在接口调用中

public interface IHallBook<T> where T : class
{
    T GetRecord(int id);
    IEnumerable<T> GetByCity(string city);
    IEnumerable <T>GetAllList();
    void AddNewRecord(T model);
    void UpdateRecord(T model);
    void DeleteRecord(int id);

    void SaveAsRecord();
 }

手动调用就在这里

public class ManupulationRecord<T> : IHallBook<T> where T : class
    {
        private DataBaseContext dbdata;
        private DbSet<T> dbEntity;

        public ManupulationRecord()
        {
            dbdata = new DataBaseContext();
            dbEntity = dbdata.Set<T>();
        } 
        public void AddNewRecord(T model)
        {
            dbEntity.Add(model);
        }

控制器

public class AllHallListController : Controller
    {
        // GET: /AllHallList/Index
        private BAL.interfaces.IHallBook<HallProfile> fromintrface;

        public AllHallListController()
        {
            this.fromintrface = new ManupulationRecord<HallProfile>();
        }

        public ActionResult Index()
        {
            ViewBag.listdata = from x in fromintrface.GetAllList() select x;
            return View(from x in fromintrface.GetAllList() select x);
        }
        // AllHallList/AddNewHallRecord

        [HttpGet]
        public ActionResult AddNewHallRecord(ClsCityList city)
        { 
            return View();
        }
        [HttpPost]
        public ActionResult AddNewHallRecord(HallProfile hall)
        {
            fromintrface.AddNewRecord(hall);
            fromintrface.SaveAsRecord();
            return View();
        }
    }

Answer 1

尝试添加到控制器：private BAL.interfaces.IHallBook<ClsCityList> cityList; 并在行动 AddNewHallRecord:

ViewBag.CityList = (from x in cityList.GetAllList() select x);
SelectList selectlistCity = new SelectList(city, "Id", "CityName");
ViewBag.CityList = selectlistCity;

在视野中：

@Html.DropDownList("CityDropDown", (IEnumerable<SelectListItem>) ViewBag.CityList , new { @class = "form-control" })