Question

假设下面是我的视图模型类。

public class MainViewModel
{
    public List<Student> Students { get; set; }
    public int SelectedState = 0;

}

public class Student
{
    public int ID = 0;
    public string Name = "";
    public int StateID = 0;
    public List<States> States { get; set; }

}

public class States
{
    public int ID = 0;
    public string Name = "";
}

现在我怎么能用名为States of students class的嵌套属性绑定下拉列表？

@Html.DropDownListFor(x => x.SelectedState new SelectList(Model.Students.States, "ID", "Name", Model.SelectedState), "-- Select States--", new { id = "cboState", @class = "edit-mode" })

这不起作用SelectList(Model.Students.States, "ID", "Name", Model.SelectedState)如何引用此Model.Students.States

请与代码示例讨论此问题。每个学生都与州有关系。

Answer 1

检查出来：

XML

但最好在Controller中的ViewBag中保存States List：

@Html.DropDownListFor(x => x.SelectedState, new SelectList(Model.Students.FirstOrDefault().States, "ID", "Name", Model.SelectedState), "-- Select States--", new { id = "cboState", @class = "edit-mode" })

在视图上：

ViewBag.States = (_context or _serviceLayer).(States or GetStates()).Select(s => new SelectListItem { Value = s.ID, Text = s.Name, Selected = s.ID == viewModel.SelectedState }).ToList();

请求编辑：

型号：

@Html.DropDownListFor(x => x.SelectedState, (List<SelectListItem>)ViewBag.States, "-- Select States--", new { id = "cboState", @class = "edit-mode" })

控制器：

namespace MyProject.Models
{
    public class ViewInfo
    {
        public int StateID { get; set; }
    }

    public class Student
    {
        public int ID { get; set; }
        public string FullName { get; set; }
        public int StateID { get; set; }
    }
    public class State
    {
        public int ID { get; set; }
        public string Name { get; set; }
    }
}

观点：

using MyProject.Models;
namespace MyProject.Controllers
{
    public class StudentsController : Controller
    {
        private MyDBEntities _context;

        public StudentsController()
        {
            this._context = new MyDBEntities();
        }

        // StudentsController
        public ActionResult Index()
        {
            ViewBag.ViewInfo = new ViewInfo { StateID = 1 };
            ViewBag.StateID = _context.States.Select(s => new SelectListItem { Value = s.ID, Text = s.Name }).ToList();
            return View(_context.Students.ToList());
        }
        [HttpPost]
        [ValidateAntiForgeryToken]
        public ActionResult Index(ViewInfo viewInfo)
        {
            ModelState.Clear();

            ViewBag.ViewInfo = viewInfo;
            ViewBag.StateID = _context.States.Select(s => new SelectListItem { Value = s.ID, Text = s.Name, Selected = s.ID == viewInfo.StateID }).ToList();
            return View(_context.Students.Where(s => s.StateID == viewInfo.StateID).ToList());
        }
    }
}

ASP.Net MVC：如何使用深层嵌套属性绑定下拉列表

1 个答案: