MVC5中的DropDownList

Question

如何使用Code First從c＃MVC5中的數據庫填充下拉列表中的數據。

這是我嘗試過的：

模型：

 public class EventBooking
{
    [Key]
    public int EventId { get; set; }
    [Required(ErrorMessage = "Enter your full name ")]
    public string FullName { get; set; }

    [Required(ErrorMessage = "Enter your phone number ")]
    [DataType(DataType.PhoneNumber)]
    public string PhoneNumber { get; set; }

    [Required(ErrorMessage = "Enter your email address ")]
    [DataType(DataType.EmailAddress)]
    public string Email { get; set; }

    [Required(ErrorMessage = "Specify your event start date ")]
    [DataType(DataType.Date)]
    public DateTime StartDate { get; set; }

    [Required(ErrorMessage = "Specify your event end date ")]
    [DataType(DataType.Date)]
    public DateTime EndDate { get; set; }

    //[Required(ErrorMessage = "Select your event")]
    public string EventType { get; set; }


    public string EventDescription { get; set; }

    [Required(ErrorMessage = "Specify the number of your event attendees ")]
    public int NumberOfAttendes { get; set; }
}

控制器：

 public ActionResult Create([Bind(Include="EventId,FullName,PhoneNumber,Email,StartDate,EndDate,EventType,EventDescription,NumberOfAttendes")] EventBooking eventBooking)

    {
        if (ModelState.IsValid)
        {
            db.EventBooking.Add(eventBooking);
            db.SaveChanges();
            return RedirectToAction("Index");
        }

        return View(eventBooking);
    }

視圖：

 <div class="form-group">
    @Html.LabelFor(model => model.EventType, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.EditorFor(model => model.EventType, new { htmlAttributes = new { @class = "form-control" } })
                @Html.ValidationMessageFor(model => model.EventType, "", new { @class = "text-danger" })
            </div>
        </div>

我無法將“事件類型”視圖更改為“下拉列表”。 誰能幫忙。

Answer 1

我已經看到了用數據填充下拉菜單的幾種不同方法，但是最終的處理方法通常是圍繞將“事件類型”放入其自己的列表中，並將其與模型一起發送回視圖。 默認的腳手架操作使用ViewBag，但是您可以在具有元數據的列表上創建自己的ViewModel或平頭釘。

我認為您的意思是Get操作而不是Post？

控制器：

// GET: /Create
public ActionResult Create()
    {
        EventBookingViewModel eventBookingViewModel = new EventBookingViewModel
        {
            EventTypes = new SelectList(methodToReturnAListToHere(), "ValueColumn", "DisplayColumn")
        };
        return View(eventBookingViewModel);
    }

視圖：

<div class="col-md-9">
     @Html.DropDownListFor(model => model.EventType, Model.EventTypes, new { @class = "form-control" })
     @Html.ValidationMessageFor(model => model.EventType)
</div>

在DropDownListFor中，第一個參數是您要在其中存儲所選值的參數，第二個參數是您希望綁定到的SelectList。

Answer 2

如下綁定MVC5中的DropDownList：

查看代碼

@model DepenInjectionINMVC5App.Controllers.DemoController.EventBooking
    @{
        ViewBag.Title = "CreateDDL";
        Layout = "~/Views/Shared/_Layout.cshtml";
    }

    <h2>CreateDDL</h2>


    <div>
        @Html.LabelFor(Model => Model.Id, "Event", new { @class = "control-label" })
        @Html.DropDownListFor(Model => Model.Id, new SelectList(ViewBag.EventList, "Id", "Name"))
    </div>

控制器代碼

public class EventBooking
{
    public int Id { get; set; }
    public string Name { get; set; }
}


public ActionResult CreateDDL()
{
    var eventList = new List<EventBooking>();
    EventBooking eventItem;
    var eventArr = new string[] { "Event-1", "Event-2", "Event-3", "Event-4", "Event-5", "Event-6", "Event-7" };
    for (int index = 0; index < eventArr.Length; index++)
    {
        eventItem = new EventBooking();
        eventItem.Id = index + 1;
        eventItem.Name = eventArr[index];
        eventList.Add(eventItem);
    }
    ViewBag.EventList = eventList;

    return View();
}

Answer 3

您要填充事件列表嗎？ 嘗試像這樣的事情可能對您有用

          <tr>
            <td>Event type</td>
            <td>
                <select @Html.EditorFor(model => model.EventType)>
                    <option>//enter you list of items you want to display here</option>   
                </select>
                    @Html.ValidationMessageFor(model => model.EventType, "", new { @class = "text-danger" })
            </td>