Question

这个问题应该很简单..我试图将我的下拉列表中的值传递给控制器..我没有收到错误，但它正在为该属性发送一个空值。请帮忙..

我的代码如下：

控制器：

    public ActionResult Create()
    {
        var list = new [] 

            { 
                new Room{ RoomID = 1, Building = "FAYARD HALL"},
                new Room{ RoomID = 2, Building = "WHATEVER HALL"},
                new Room{ RoomID = 3, Building = "TIME SQUARE"},
                new Room{ RoomID = 4, Building = "MISSISSIPPI"},
                new Room{ RoomID = 5, Building = "NEW YORK"},

            };


        var selectList = new SelectList(list,"RoomID", "Building");
        ViewData["BuildingList"] = selectList;  

        return View();
    }

    //
    // POST: /Room/Create

    [HttpPost]
    [ValidateAntiForgeryToken]
    public ActionResult Create(Room room)
    {
        if (ModelState.IsValid)
        {
            db.Rooms.Add(room);
            db.SaveChanges();
            return RedirectToAction("Index");
        }

        return View(room);
    }

我的观点：

    <div>
        @Html.LabelFor(model => model.Building, "Building")
    </div>
    <div>

        @Html.DropDownList("BuildingList", String.Empty)
        @Html.ValidationMessageFor(model => model.Building)
    </div>

请帮忙......

谢谢。

Answer 1

您的下拉是否已填充？鉴于您的代码，我认为您需要以下内容：

@Html.DropDownListFor(model => model.Building, ViewData["BuildingList"])

即。将所选值绑定到Building的{{1}}属性，并使用视图模型中的下拉列表填充列表。

我也不确定这是你的意图。您正在填写一个带有房间的下拉列表，然后根据您创建新房间的选择，这似乎有点可疑。

修改

好的，我会让你的事情变得更轻松。

我将从你的课程开始。这是我假设您正在与之合作的房间：

Room

现在让我们做一些比使用ViewData更好的事情。我为你创建了一个视图模型。您将使用选择列表填充此内容，并且当您发布表单时，您在视图中选择的项目将绑定到public class Room { public int RoomId { get; set; } public string Building { get; set; } }。

SelectedRoomId

<强>控制器

public class ViewModel { public int SelectedRoomId { get; set; } public SelectList RoomOptions { get; set; } }

查看

private SelectList GetSelectList() { var list = new[] { new Room { RoomId = 1, Building = "FAYARD HALL"}, new Room { RoomId = 2, Building = "WHATEVER HALL"}, new Room { RoomId = 3, Building = "TIME SQUARE"}, new Room { RoomId = 4, Building = "MISSISSIPPI"}, new Room { RoomId = 5, Building = "NEW YORK"} }; return new SelectList(list, "RoomId", "Building"); } public ActionResult Create() { ViewModel viewModel = new ViewModel { RoomOptions = GetSelectList() }; return View(viewModel); } [HttpPost] public ActionResult Create(ViewModel viewModel) { if (ModelState.IsValid) { // Save here // create a new room using the SelectedOptionId in the viewModel return RedirectToAction("Index", "Home"); } // repopulate the list if something failed viewModel.RoomOptions = GetSelectList(); return View(viewModel); }

试过并测试过。祝你好运！

Answer 2

模型绑定是在mvc。{/ p>中的names property的帮助下进行的

在您的情况下，您的控件名称为BuildingList：

@Html.DropDownList("BuildingList", (SelectList)ViewData["BuildingList"])

因此，在您的控制器上，操作将如下所示：

[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Create(FormCollection collection)
{
   var selectedValue = collection["BuildingList"];
}

下拉列表值未传递给控制器

2 个答案: