dropdownlist看起来不错，但不起作用 [英] dropdownlist looks OK but not working
本文介绍了dropdownlist看起来不错，但不起作用的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我正在尝试在ASP.net MVC中进行编码，而我的代码看起来像:
I am trying to code in asp net MVC and my code looks:
控制器:
public class ReservationsController : Controller
{
private AppDbContext db = new AppDbContext();
// GET: Reservations
public ActionResult Index()
{
return View(db.Reservations.ToList());
}
// GET: Reservations/Create
public ActionResult Create()
{
ViewBag.ScreeningId = new SelectList(db.Screenings, "Id", "Description");
HashSet<int> seats = new HashSet<int>(db.Reservations.Select(x => x.SeatNumber));
ViewBag.Seats = seats;
return View();
}
查看:
<div class="form-group">
@Html.LabelFor(model => model.Screening, "Seans", htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.DropDownList("ScreeningId", null, htmlAttributes: new { @class = "form-control" })
@Html.ValidationMessageFor(model => model.Screening, "", new { @class = "text-danger" })
</div>
</div>
型号:
public class Reservation
{
public int Id { get; set; }
[DisplayName("Imię")]
public string FirstName { get; set; }
[DisplayName("Nazwisko")]
public string SecondName { get; set; }
[DisplayName("Telefon")]
public string Phone { get; set; }
public int? ScreeningId { get; set; }
[DisplayName("Seans")]
public Screening Screening { get; set; }
[DisplayName("Numer miejsca")]
public int SeatNumber { get; set; }
}
我收到错误消息:
没有类型为'IEnumerable<的ViewData项.具有键"ScreeningId"的SelectListItem>.
There is no ViewData item of type 'IEnumerable< SelectListItem >' that has the key 'ScreeningId'.
有人知道怎么了?
Create.cshtml已满
Create.cshtml FULL
@model CinemaTicketReservation.Models.Reservation
@{
ViewBag.Title = "Rezerwacja filmu";
}
<h2>Zarezerwuj film</h2>
@using (Html.BeginForm())
{
@Html.AntiForgeryToken()
<div class="form-horizontal">
<hr />
@Html.ValidationSummary(true, "", new { @class = "text-danger" })
<div class="form-group">
@Html.LabelFor(model => model.FirstName, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.EditorFor(model => model.FirstName, new { htmlAttributes = new { @class = "form-control" } })
@Html.ValidationMessageFor(model => model.FirstName, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.SecondName, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.EditorFor(model => model.SecondName, new { htmlAttributes = new { @class = "form-control" } })
@Html.ValidationMessageFor(model => model.SecondName, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.Phone, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.EditorFor(model => model.Phone, new { htmlAttributes = new { @class = "form-control" } })
@Html.ValidationMessageFor(model => model.Phone, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.SeatNumber, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.EditorFor(model => model.SeatNumber, new { htmlAttributes = new { @class = "form-control" } })
@Html.ValidationMessageFor(model => model.SeatNumber, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.Screening, "Seans", htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.DropDownList("ScreeningId", null, htmlAttributes: new { @class = "form-control" })
@Html.ValidationMessageFor(model => model.Screening, "", new { @class = "text-danger" })
</div>
</div>
<table class="table table-bordered w400">
@for (var i = 0; i < 5; i++)
{
<tr>
@for (var j = 0; j < 5; j++)
{
var k = i * 5 + j + 1;
if (((HashSet<int>) ViewBag.Seats).Contains(k))
{
<td class="red">@k</td>
}
else
{
<td class="green">@k</td>
}
}
</tr>
}
</table>
<br />
<div class="form-group">
<div class="col-md-offset-2 col-md-10">
<input type="submit" value="Rezerwuj" class="btn btn-default" />
</div>
</div>
</div>
}
@if (Session["Login"] != null)
{
<div>
@Html.ActionLink("Powrót", "Index")
</div>
}
@section Scripts {
@Scripts.Render("~/bundles/jqueryval")
}
ReservationController已满:
ReservationController FULL:
public class ReservationsController : Controller
{
private AppDbContext db = new AppDbContext();
// GET: Reservations
public ActionResult Index()
{
return View(db.Reservations.ToList());
}
// GET: Reservations/Create
public ActionResult Create()
{
ViewBag.ScreeningId = new SelectList(db.Screenings, "Id", "Description");
HashSet<int> seats = new HashSet<int>(db.Reservations.Select(x => x.SeatNumber));
ViewBag.Seats = seats;
return View();
}
// POST: Reservations/Create
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Create([Bind(Include = "Id,FirstName,SecondName,Phone,SeatNumber")] Reservation reservation)
{
if (ModelState.IsValid)
{
// sprawdzamy czy miejsce bylo juz zajete
if (db.Reservations.Select(x => x.SeatNumber).Contains(reservation.SeatNumber))
{
return View(reservation);
}
db.Reservations.Add(reservation);
db.SaveChanges();
if (Session["Login"] != null)
{
return RedirectToAction("Index");
}
return RedirectToAction("Success");
}
return View(reservation);
}
public ActionResult Success()
{
return View();
}
// GET: Reservations/Edit/5
public ActionResult Edit(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
Reservation reservation = db.Reservations.Find(id);
if (reservation == null)
{
return HttpNotFound();
}
return View(reservation);
}
// POST: Reservations/Edit/5
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Edit([Bind(Include = "Id,FirstName,SecondName,Phone,SeatNumber")] Reservation reservation)
{
if (ModelState.IsValid)
{
db.Entry(reservation).State = EntityState.Modified;
db.SaveChanges();
return RedirectToAction("Index");
}
return View(reservation);
}
// GET: Reservations/Delete/5
public ActionResult Delete(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
Reservation reservation = db.Reservations.Find(id);
if (reservation == null)
{
return HttpNotFound();
}
return View(reservation);
}
// POST: Reservations/Delete/5
[HttpPost, ActionName("Delete")]
[ValidateAntiForgeryToken]
public ActionResult DeleteConfirmed(int id)
{
Reservation reservation = db.Reservations.Find(id);
db.Reservations.Remove(reservation);
db.SaveChanges();
return RedirectToAction("Index");
}
这是您想要的吗?模型在第一篇文章中.
This is what you wanted? Model is in first post.
推荐答案
在您的控制器中，也不要忘记在POST操作中填充 ViewBag.ScreeningId :
In your controller, don't forget to populate ViewBag.ScreeningId in POST action too :
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Create([Bind(Include = "Id,FirstName,SecondName,Phone,SeatNumber")] Reservation reservation)
{
ViewBag.ScreeningId = new SelectList(db.Screenings, "Id", "Description");
[...]
这篇关于dropdownlist看起来不错，但不起作用的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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