自加载实体以来，实体可能已被修改或删除。 （ASP.NET MVC）

Question

I try to update one property in table from SelectedList

Here is my model

 public partial class Interwier
{
    [Key]
    public int Interwier_id { get; set; }
    [Display(Name = "ФИО")]
    public string FIO { get; set; }
    [Display(Name = "Email")]
    public string Email { get; set; }
    [Display(Name = "Телефон")]
    public string Telephone { get; set; }
    [Display(Name = "День рождения")]
    public System.DateTime Birthday { get; set; }
    [Display(Name = "Город")]
    public string City { get; set; }
    [Display(Name = "Зарплата")]
    public string Salary { get; set; }
    [Display(Name = "Английский язык")]
    public string English { get; set; }
    public Nullable<int> VacancyId { get; set; }
    public string Status { get; set; }

    public virtual Vacancy Vacancy { get; set; }
}

I need to update Status property.

Here is Edit action in controller

public ActionResult Edit(int? id)
    {
        if (id == null)
        {
            return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
        }
        Interwier interwierModel = db.InterwierModels.Find(id);
        if (interwierModel == null)
        {
            return HttpNotFound();
        }
        return View(interwierModel);
    }

    // POST: Interwier/Edit/5
    // 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 Edit([Bind(Include = "Id,Email,Telephone,Birthday,City,Salary,English,Status")] Interwier interwierModel)
    {
        if (ModelState.IsValid)
        {
            db.Entry(interwierModel).State = EntityState.Modified;
            db.SaveChanges();
            return RedirectToAction("Incoming");
        }
        return View(interwierModel);
    }

And here is how it looks on View

<div class="form-group" style="padding-left: 515px;">
        <div class="col-md-10">

            @Html.DropDownListFor(model => model.Status, new[]
                {
                    new SelectListItem() {Text = "Подтвердить", Value = "Одобрено"},
                    new SelectListItem() {Text = "Отправить в архив", Value = "Архив"},
                }, "Статус", new { @class = "form-control" })

        </div>
    </div>

When I click submit button I have this error

How I can handle this?

Answer 1

You need to include Interwier_id property as hidden field. Use HiddenFor extension method. You don't post the ID to server that's why EF cannot find the entity in DB. Assuming the code below is within the BeginForm block.

@Html.DropDownListFor(model => model.Interwier_id)

<div class="form-group" style="padding-left: 515px;">
    <div class="col-md-10">

        @Html.DropDownListFor(model => model.Status, new[]
            {
                new SelectListItem() {Text = "Подтвердить", Value = "Одобрено"},
                new SelectListItem() {Text = "Отправить в архив", Value = "Архив"},
            }, "Статус", new { @class = "form-control" })

    </div>
</div>

And also update properties that you bind from Id to Interwier_id:

[Bind(Include = "Interwier_id,...")]