傳遞給HttpPost方法時，模型ID更改

Question

我正在重構MvcMusicStore代碼，並且正在更新StoreManagerController。 我將“編輯”操作更改為以下內容：

    //
    // GET: /StoreManager/Edit/5

    public ActionResult Edit(int id)
    {
        Toy toy = dbStore.Toys.Find(id);
        ViewBag.CategoryId = new SelectList(dbStore.Categories, "CategoryId", "Name", toy.CategoryId);
        ViewBag.BrandId = new SelectList(dbStore.Brands, "BrandId", "Name", toy.BrandId);
        return View(toy);
    }

    //
    // POST: /StoreManager/Edit/5

    [HttpPost]
    public ActionResult Edit(Toy toy)
    {
        if (ModelState.IsValid)
        {
            dbStore.Entry(toy).State = EntityState.Modified;
            dbStore.SaveChanges();
            return RedirectToAction("Index");
        }
        ViewBag.CategoryId = new SelectList(dbStore.Categories, "CategoryId", "Name", toy.CategoryId);
        ViewBag.BrandId = new SelectList(dbStore.Brands, "BrandId", "Name", toy.BrandId);
        return View(toy);
    }

在測試過程中，當我單擊“ Edit操作時，該視圖顯示良好，並且在Edit(int id)方法中設置了一個斷點，顯示ToyId為1。但是，在進行更改並單擊“保存”后，將通過Toy對象方法ActionResult Edit(Toy toy)的錯誤ToyId等於0。

修改發生在哪里，還是從視圖傳回了toy的副本，並且沒有正確地在ToyId上復制玩具？

更新：添加了編輯視圖的帖子

@model Store.Models.Toy

@{
    ViewBag.Title = "Edit";
}

<h2>Edit</h2>

<script src="@Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript">      </script>
<script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")"   type="text/javascript"></script>

@using (Html.BeginForm()) {
@Html.ValidationSummary(true)
<fieldset>
    <legend>Toy</legend>

    @Html.HiddenFor(model => model.ToyId)

    <div class="editor-label">
        @Html.LabelFor(model => model.CategoryId, "Category")
    </div>
    <div class="editor-field">
        @Html.DropDownList("CategoryId", String.Empty)
        @Html.ValidationMessageFor(model => model.CategoryId)
    </div>

    <div class="editor-label">
        @Html.LabelFor(model => model.BrandId, "Brand")
    </div>
    <div class="editor-field">
        @Html.DropDownList("BrandId", String.Empty)
        @Html.ValidationMessageFor(model => model.BrandId)
    </div>

    <div class="editor-label">
        @Html.LabelFor(model => model.Title)
    </div>
    <div class="editor-field">
        @Html.EditorFor(model => model.Title)
        @Html.ValidationMessageFor(model => model.Title)
    </div>

    <div class="editor-label">
        @Html.LabelFor(model => model.Price)
    </div>
    <div class="editor-field">
        @Html.EditorFor(model => model.Price)
        @Html.ValidationMessageFor(model => model.Price)
    </div>

    <div class="editor-label">
        @Html.LabelFor(model => model.PictureUrl)
    </div>
    <div class="editor-field">
        @Html.EditorFor(model => model.PictureUrl)
        @Html.ValidationMessageFor(model => model.PictureUrl)
    </div>

    <p>
        <input type="submit" value="Save" />
    </p>
</fieldset>
}

<div>
    @Html.ActionLink("Back to List", "Index")
</div>

玩具類

[Bind(Exclude = "ToyId")]
public class Toy
{
    [ScaffoldColumn(false)]
    public int ToyId { get; set; }

    // ... other stuff here
}

Answer 1

是因為

[Bind(Exclude = "ToyId")] 

因此，ToyID屬性實際上在綁定操作中被忽略，並且未使用隱藏值。

您可以簡單地從類中刪除它，以便ToyId從POST操作中正確綁定。 或者，您可以通過將id路由值復制到Toy的ToyId屬性中（或添加名為id的方法參數以使其自動綁定）來在控制器方法中手動綁定它。

但是，允許綁定ID屬性等存在一些潛在的問題，而另一SO提供了一個進入此窗口的窗口： ASP.NET MVC-[Bind（Exclude =“ Id”）]的替代方法