找不到现有的财产

Question

我正在尝试在ASP.NET中创建一个下拉框，当生成View时，它会给我一个错误，说明在模型分类中找不到Categorie_ID（它确实存在并且它是公共的和所有）。成功地加载了类别和产品（我调试了那部分）。

这是我得到的;

我的观点：

@{
ViewBag.Title = @Model.Product.Merk; @Model.Product.Type;;
Layout = "~/Views/Shared/_Layout.cshtml";
}
@model WebshopProjectBlokC.ViewModels.ProductViewModel      
<h2>@Model.Product.Merk @Model.Product.Type wijzigen</h2>
@using (Html.BeginForm("ProductWijzigenForm", "ProductBeheer"))
{
    @Html.ValidationSummary(true)

    <fieldset>
        @Html.HiddenFor(model => model.Product.ID)
        @Html.HiddenFor(model => model.Product.Naam)
        <div class="editor-label">Prijs</div>
        <div class="editor-field"> 
            @Html.TextBoxFor(model => model.Product.Prijs)
            @Html.ValidationMessageFor(model => model.Product.Prijs)</div>
        <div class="editor-label">Maat</div>
        <div class="editor-field"> 
            @Html.TextBoxFor(model => model.Product.Maat)
            @Html.ValidationMessageFor(model => model.Product.Maat)</div>
        <div class="editor-label">Merk</div>
        <div class="editor-field"> 
            @Html.TextBoxFor(model => model.Product.Merk)
            @Html.ValidationMessageFor(model => model.Product.Merk)</div>
        <div class="editor-label">Type</div>
        <div class="editor-field"> 
            @Html.TextBoxFor(model => model.Product.Type)
            @Html.ValidationMessageFor(model => model.Product.Type)</div>
        <div class="editor-field">
            @Html.DropDownListFor(model => model.SelectedID, Model.Categorien)
        </div>
        <div class="editor-label">URL Foto</div>
        <div class="editor-field"> 
            @Html.TextBoxFor(model => model.Product.Afbeelding)
            @Html.ValidationMessageFor(model => model.Product.Afbeelding)</div>
        <input type="submit" value="Wijzig" />
    </fieldset>
}

控制器：

    public ActionResult ProductWijzig(int productid)
    {
        ProductViewModel viewModel = new ProductViewModel();
        Product product = ProductdataController.GetProduct(productid);
        List<Categorie> catas = ProductdataController.HaalCategorienOp();
        viewModel.Categorien = new SelectList(catas, "Categorie_id", "Naam");
        viewModel.Product = product;
        return View(viewModel);
    }

viewmodel：

namespace WebshopProjectBlokC.ViewModels
{
   public class ProductViewModel
   {
       public Product Product { get; set; }
       public Categorie Categorie { get; set; }
       public SelectList Categorien { get; set; }
       public int SelectedID { get; set; }
   }

}

HaalCategorienOp方法;

    public List<Categorie> HaalCategorienOp()
    {
        List<Categorie> categorien = new List<Categorie>();
        try
        {
            conn.Open();

            string selecteer = "select * from categorie";
            MySqlCommand command = new MySqlCommand(selecteer, conn);
            MySqlDataReader dataReader = command.ExecuteReader();

            while (dataReader.Read())
            {
                Categorie categorie = HaalCategorieUitReader(dataReader);
                categorien.Add(categorie);
            }
        }
        catch (Exception e)
        {
            Console.Write("Ophalen van categorien mislukt " + e);
            throw e;
        }
        finally
        {
            conn.Close();
        }

        return categorien;
    }

HaalCategorieUitReader方法;

  protected Categorie HaalCategorieUitReader(MySqlDataReader datareader)
    {
        if (!datareader.IsDBNull(0))
        {
            categorie_id = datareader.GetInt32("categorie_id");
        }
        if (!datareader.IsDBNull(1))
        {
            categorienaam = datareader.GetString("naam");
        }
        if (!datareader.IsDBNull(2))
        {
            hoofdcategorie = datareader.GetInt32("hoofdcategorie");
        }

        Categorie categorie = new Categorie{ Categorie_id = categorie_id, Hoofdcategorie = hoofdcategorie, Naam = categorienaam};

        return categorie;
    }