MVC未将所选值返回给控制器

Question

我无法从下拉菜单中将所选值返回给控制器。我在网上搜索，但找不到任何内容（可能是我在找错东西的错误）

我希望我给了您解决我的问题所需的代码。如果您解释原因，那也很好，因为我想从我的过失中学习一些东西。

我的班级菜单：

public class Menu
{
    public int Id { get; set; }
    [Required]
    public string Naam { get; set; }
    [Required]
    public decimal Prijs { get; set; }
    public Gerecht Voorgerecht { get; set; }
    public Gerecht Hoofdgerecht { get; set; }
    public Gerecht Nagerecht { get; set; }
}

我的班子Gerecht：

public class Gerecht
{
    public int Id { get; set; }
    [Required]
    public string Naam { get; set; }
}

我的模型视图：

public class MenuViewModel
{
    public int Id { get; set; }
    [Required]
    public string Naam { get; set; }
    [Required]
    public decimal Prijs { get; set; }
    public IEnumerable<Gerecht> Voorgerecht;
    public IEnumerable<Gerecht> Hoofdgerecht;
    public IEnumerable<Gerecht> Nagerecht;
}

我的Createhtml：

        <div class="form-group">
            @Html.LabelFor(model => model.Voorgerecht, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.DropDownListFor(model => model.Voorgerecht, new SelectList(Model.Voorgerecht, "Id", "Naam"), "Select a  product")
            </div>
        </div>

        <div class="form-group">
            @Html.LabelFor(model => model.Hoofdgerecht, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.DropDownListFor(model => model.Hoofdgerecht, new SelectList(Model.Hoofdgerecht, "Id", "Naam"), "Select a  product")
            </div>
        </div>

        <div class="form-group">
            @Html.LabelFor(model => model.Nagerecht, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.DropDownListFor(model => model.Nagerecht, new SelectList(Model.Nagerecht, "Id", "Naam"), "Select a  product")
            </div>
        </div>

我的控制器：

    // GET: Menus/Create
public ActionResult Create()
{
    var menuViewModel = new MenuViewModel();
    menuViewModel.Voorgerecht = db.Gerechts.ToList();
    menuViewModel.Hoofdgerecht = db.Gerechts.ToList();
    menuViewModel.Nagerecht = db.Gerechts.ToList();
    return View(menuViewModel);
}

// POST: Menus/Create
// To protect from overposting attacks, please enable the specific properties you want to bind to, for 
// more details see http://go.microsoft.com/fwlink/?LinkId=317598.
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Create([Bind(Include = "Id,Naam,Prijs")] MenuViewModel menu)
{
    if (ModelState.IsValid)
    {
        Gerechten gerecht = new Gerechten();
        Menu menutjes = new Menu();
        menutjes.Id = menu.Id;
        menutjes.Naam = menu.Naam;
        menutjes.Prijs = menu.Prijs;
        //gerecht = menu.Voorgerecht;
        //menutjes.Voorgerecht = menu.Voorgerecht.;
        //menutjes.Hoofdgerecht = menu.Hoofdgerecht;
        //menutjes.Nagerecht = menu.Nagerecht;
        db.Menus.Add(menutjes);
        db.SaveChanges();
        return RedirectToAction("Index");
    }

    var menuViewModel = new MenuViewModel();
    menuViewModel.Voorgerecht = db.Gerechts.ToList();
    menuViewModel.Hoofdgerecht = db.Gerechts.ToList();
    menuViewModel.Nagerecht = db.Gerechts.ToList();
    return View(menuViewModel);
}