Question

我使用VS2015中的自动脚手架工具创建了一个网站。在edit.cshtml页面上，来自相关表的两个字段（每个字段中的主键）显示为下拉列表。我只想显示每个相关表中的那些字段的值，而不是下拉列表，因为这些值不应该是可编辑的。

在控制器中，我删除了ViewBag。（字段）。在视图中，我将字段更改为@ Html.DisplayFor（...）而不是@ Html.DropDownList（...）。现在页面显示正确，但是当我保存编辑时，我收到以下错误： UPDATE语句与FOREIGN KEY约束冲突...

仪器型号：

    public partial class equipment
    {
(...) 
        public int id { get; set; }
        public int tmde_id { get; set; }
        public int acct_id { get; set; }
        [DisplayName("ID")]
        public string instrument_id { get; set; }
        [DisplayName("S/N")]
        public string serial_nbr { get; set; }
        public string dept { get; set; }
(...)
        public virtual account account { get; set; }
        public virtual tmde tmde { get; set; }
(...)

控制器：

        // GET: Instruments/Edit/5
        public ActionResult Edit(int? id)
        {
            if (id == null)
            {
                return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
            }
            equipment equipment = db.equipment.Find(id);
            if (equipment == null)
            {
                return HttpNotFound();
            }

            ViewBag.acct_id = new SelectList(db.account, "id", "acct_nbr", equipment.acct_id);
            ViewBag.tmde_id = new SelectList(db.tmde, "id", "noun", equipment.tmde_id);
            return View(equipment);
        }

        // POST: Instruments/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,tmde_id,acct_id,instrument_id,serial_nbr,dept,location,on_site,cal_cycle,cal_interval,edit_user,edit_date,active,cal_due,short_note")] equipment equipment)
        {
            if (ModelState.IsValid)
            {
                db.Entry(equipment).State = EntityState.Modified;
                db.SaveChanges();
                return RedirectToAction("Index");
            }
            ViewBag.acct_id = new SelectList(db.account, "id", "acct_nbr", equipment.acct_id);
            ViewBag.tmde_id = new SelectList(db.tmde, "id", "noun", equipment.tmde_id);
            return View(equipment);
        }

查看编辑页面：

(...)
        @Html.ValidationSummary(true, "", new { @class = "text-danger" })
        @Html.HiddenFor(model => model.id)

        @Html.LabelFor(model => model.instrument_id, htmlAttributes: new { @class = "control-label col-md-2" })
        @Html.EditorFor(model => model.instrument_id, new { htmlattributes = new { @class = "form-control" } })
        @Html.ValidationMessageFor(model => model.instrument_id, "", new { @class = "text-danger" })
        <br />
        @Html.LabelFor(model => model.account.name)
        @Html.DropDownList("acct_id", null, htmlAttributes: new { @class = "form-control" })
        <br />
        @Html.LabelFor(model => model.tmde.noun)
        @Html.DisplayFor(model => model.tmde.noun)
        @Html.DropDownList("tmde_id", null, htmlAttributes: new { @class = "form-control" })
        <br />
        @Html.LabelFor(model => model.tmde.mfr)
        @Html.DisplayFor(model => model.tmde.mfr)
        <br />
        @Html.LabelFor(model => model.tmde.model)
        @Html.DisplayFor(model => model.tmde.model)
        <br />
        @Html.LabelFor(model => model.serial_nbr)
        @Html.DisplayFor(model => model.serial_nbr)
        <br />

Answer 1

我终于想出了如何做到这一点！模特很好。以下是我所做的更改：

<强>控制器：替换

ViewBag.acct_id = new SelectList(db.account, "id", "acct_nbr", equipment.acct_id);
ViewBag.tmde_id = new SelectList(db.tmde, "id", "noun", equipment.tmde_id);
return View(equipment);

。通过

ViewBag.acct_id = equipment.acct_id; ViewBag.tmde_id = equipment.tmde_id; return View(equipment);

<强> Edit.cshtml ：已添加到页面顶部

@Html.HiddenFor(model => model.tmde_id) @Html.HiddenFor(model => model.acct_id)

在我显示各个字段的正文中：

<dt>@Html.LabelFor(model => model.tmde.noun)</dt> <dd>@Html.DisplayFor(model => model.tmde.noun)</dd>

我可以显示设备表中的任何字段以及相关表格。

此代码确保维护外键（隐藏，因为它们不能由用户编辑），同时仍允许编辑设备表中的其他字段。现在数据库UPDATE完美运行。

希望这会帮助可能遇到相同情况的其他人。

MVC删除编辑时的下拉列表

1 个答案: