我在更新过程中收到此错误。有人可以帮我吗？

Question

[请查看我的以下与文件名相对应的代码：-我正在使用实体框架，并且将变量urun设置为null，因此无法对其进行更新。请帮助。

UrunController-

 public ActionResult UrunGetir(int id)
        {
            var product = db.Urunler.Find(id);

            IEnumerable<SelectListItem> basetypes = db.Kategoriler.Select(
            b => new SelectListItem { Value = b.kategoriID.ToString(), Text = b.kategoriAd });
            ViewData["basetype"] = basetypes;

            return View("UrunGetir", product);
        }

public ActionResult Guncelle(Urunler p)
    {
        var urun = db.Urunler.Find(p.urunID);
        urun.urunAd = p.urunAd;
        urun.urunMarka = p.urunMarka;
        urun.urunStok = p.urunStok;
        urun.urunFiyat = p.urunFiyat;

        //pr.urunKategori = product.urunKategori;
        var category = db.Kategoriler.Where(m => m.kategoriID == p.Kategoriler.kategoriID).FirstOrDefault();
        urun.urunKategori = category.kategoriID;

        db.SaveChanges();
        return RedirectToAction("Index");
    }

UrunGetir.cshtml-

@model StokTakip.Models.Entity.Urunler
@{
    ViewBag.Title = "UrunGetir";
    Layout = "~/Views/Shared/_MainLayout.cshtml";
}

<style>
    .form-content {
        padding: 5%;
        border: 1px solid #ced4da;
        margin-bottom: 2%;
    }

    .form-control {
        border-radius: 1.5rem;
    }

    .btnSubmit {
        border: none;
        border-radius: 1.5rem;
        padding: 1%;
        width: 20%;
        cursor: pointer;
        background: #0062cc;
        color: #fff;
    }
</style>

@using (Html.BeginForm("Guncelle", "Urun", FormMethod.Post))
{
    <div class="register-form">
        <div class="form">

            <div class="form-content">
                <div class="row">
                    <div class="col-md-8">
                        <div class="form-group">
                            <label>Ürün Adı :</label>
                            @*<input type="text" class="form-control" name="urunAd" />*@
                            @Html.TextBoxFor(m=> m.urunAd, new { @class="form-control"})
                        </div>
                        <div class="form-group">
                            <label>Ürün Marka :</label>
                            @*<input type="text" class="form-control" name="urunMarka" />*@
                            @Html.TextBoxFor(m=> m.urunMarka, new {@class="form-control" })
                        </div>

                        <div class="form-group">
                            <label>Ürün Kategori :</label>

                            @*@Html.TextBoxFor(m=> m.urunKategori,new { @class="form-control"})*@
                            @Html.DropDownListFor(m => m.Kategoriler.kategoriID, ViewBag.basetype as IEnumerable<SelectListItem>, new { @class = "form-control" })
                        </div>
                        <div class="form-group">
                            <label>Ürün Fiyat :</label>
                            @*<input type="text" class="form-control" name="urunFiyat" />*@

                            @Html.TextBoxFor(m=> m.urunFiyat,new {@class="form-control" })
                        </div>
                        <div class="form-group">
                            <label>Ürün Stok :</label>
                            @*<input type="text" class="form-control" name="urunStok" />*@
                            @Html.TextBoxFor(m => m.urunStok, new { @class = "form-control" })

                        </div>

                    </div>

                </div>

                <button class="btnSubmit"> Güncelle</button>
                <a href="/Urun/Index/" class="btnSubmit" style="background-color:red;">Geri Dön</a>
            </div>
        </div>
    </div>
}

Index.cshtml-

@using StokTakip.Models.Entity
@model List<Urunler>


@{
    ViewBag.Title = "Index";
    Layout = "~/Views/Shared/_MainLayout.cshtml";
}

<a style="margin-bottom:20px;" href="/Urun/UrunEkle/" class="btn btn-primary">Yeni Ürün Ekle</a>
<table class="table table-striped">
    <thead>
        <tr>
            <th scope="col">#</th>
            <th scope="col">Ürün Adı</th>
            <th scope="col"> Marka</th>
            <th scope="col"> Kategori</th>
            <th scope="col"> Fiyat</th>
            <th scope="col"> Stok</th>
            <th scope="col"> Sil</th>
            <th scope="col"> Güncelle</th>

        </tr>
    </thead>
    <tbody>
        @foreach (var product in Model)
        {
            <tr>
                <th scope="row">@product.urunID</th>
                <td>@product.urunAd</td>
                <td>@product.urunMarka</td>
                <td>@product.Kategoriler.kategoriAd</td>
                <td>@product.urunFiyat <strong>₺</strong> </td>
                <td>@product.urunStok</td>
                <td><a href="/Urun//Sil/@product.urunID" class="btn btn-danger">Sil</a></td>
                <td><a href="/Urun//UrunGetir/@product.urunID" class="btn btn-success">Güncelle</a></td>

            </tr>
        }



    </tbody>
</table>

var urun = db.Urunler.Find(p.urunID);

产品变量为null，因此我无法对其进行更新。数据库中没有问题。我正在使用实体框架。谁能帮我解决问题？

Answer 1

请添加

@Html.HiddenFor(t=> t.urunID)

在UrunGetir.cshtml中