C# 在ASP.NET MVC中填充DropDownListFor的混淆

我刚开始使用ASP.NET MVC，在@Html.DropDownListFor属性方面遇到了一些困难，我无法理解它！希望有人能帮我一把

我正在尝试在ASP.NETMVC4中重新构建此页面（）。如果有人能帮助我，如果你能提供一个如何让“团队规模”实地工作的例子，那就太好了。我已经包括了到目前为止我所做的事情。谢谢你的帮助

查看模型：

namespace ThePines.ViewModels
{
    public class EnquiryForm
    {
        [Required(ErrorMessage = "* Please enter a first name")]
        public string FirstName { get; set; }

        [Required(ErrorMessage = "* Please enter a last name")]
        public string LastName { get; set; }

        [Required(ErrorMessage = "* Please enter an email address")]
        [EmailAddress(ErrorMessage = "* Please enter a valid email address")]
        public string EmailAddress { get; set; }

        [Required(ErrorMessage = "* Please enter a country")]
        public string Country { get; set; }

        [Required(ErrorMessage = "* Please enter a question")]
        public string Question { get; set; }
    }
}

@using (Html.BeginForm("Index", "Enquiries", FormMethod.Post, new { enctype = "multipart/form-data"}))
{
    @Html.ValidationSummary(true)

    <fieldset>
        <table cellpadding="8" cellspacing="8">
            <tr>
                <td>@Html.LabelFor(model => model.FirstName, "First Name")</td>
                <td>@Html.TextBoxFor(model => model.FirstName)</td>
                <td>@Html.ValidationMessageFor(model => model.FirstName)</td>
            </tr>

            <tr>
                <td>@Html.LabelFor(model => model.LastName, "Last Name")</td>
                <td>@Html.TextBoxFor(model => model.LastName)</td>
                <td>@Html.ValidationMessageFor(model => model.LastName)</td>
            </tr>

            <tr>
                <td>@Html.LabelFor(model => model.EmailAddress, "Email Address")</td>
                <td>@Html.TextBoxFor(model => model.EmailAddress)</td>
                <td>@Html.ValidationMessageFor(model => model.EmailAddress)</td>
            </tr>

            <tr>
                <td>@Html.LabelFor(model => model.Country, "Country")</td>
                <td>@Html.TextBoxFor(model => model.Country)</td>
                <td>@Html.ValidationMessageFor(model => model.Country)</td>
            </tr>

            <tr>
                <td>@Html.LabelFor(model => model.PartySize, "Party Size")</td>
                <td>@Html.DropDownListFor()</td>
                <td>@Html.ValidationMessageFor(model => model.PartySize)</td>
            </tr>

            <tr>
                <td>@Html.LabelFor(model => model.Question, "Question")</td>
                <td>@Html.TextBoxFor(model => model.Question)</td>
                <td>@Html.ValidationMessageFor(model => model.Question)</td>
            </tr>
        </table>

        <input type="submit" value="Send Enquiry" />
    </fieldset>
}

public class EnquiriesController : Controller
{
    //
    // GET: /Enquiries/

    public ActionResult Index()
    {

    }

    // POST: /Enquiries/

    [HttpPost]
    public ActionResult Index(EnquiryForm enquiryForm)
    {
        if (ModelState.IsValid)
        {

        }

        return View(enquiryForm);
    }
}

查看：

namespace ThePines.ViewModels
{
    public class EnquiryForm
    {
        [Required(ErrorMessage = "* Please enter a first name")]
        public string FirstName { get; set; }

        [Required(ErrorMessage = "* Please enter a last name")]
        public string LastName { get; set; }

        [Required(ErrorMessage = "* Please enter an email address")]
        [EmailAddress(ErrorMessage = "* Please enter a valid email address")]
        public string EmailAddress { get; set; }

        [Required(ErrorMessage = "* Please enter a country")]
        public string Country { get; set; }

        [Required(ErrorMessage = "* Please enter a question")]
        public string Question { get; set; }
    }
}

@using (Html.BeginForm("Index", "Enquiries", FormMethod.Post, new { enctype = "multipart/form-data"}))
{
    @Html.ValidationSummary(true)

    <fieldset>
        <table cellpadding="8" cellspacing="8">
            <tr>
                <td>@Html.LabelFor(model => model.FirstName, "First Name")</td>
                <td>@Html.TextBoxFor(model => model.FirstName)</td>
                <td>@Html.ValidationMessageFor(model => model.FirstName)</td>
            </tr>

            <tr>
                <td>@Html.LabelFor(model => model.LastName, "Last Name")</td>
                <td>@Html.TextBoxFor(model => model.LastName)</td>
                <td>@Html.ValidationMessageFor(model => model.LastName)</td>
            </tr>

            <tr>
                <td>@Html.LabelFor(model => model.EmailAddress, "Email Address")</td>
                <td>@Html.TextBoxFor(model => model.EmailAddress)</td>
                <td>@Html.ValidationMessageFor(model => model.EmailAddress)</td>
            </tr>

            <tr>
                <td>@Html.LabelFor(model => model.Country, "Country")</td>
                <td>@Html.TextBoxFor(model => model.Country)</td>
                <td>@Html.ValidationMessageFor(model => model.Country)</td>
            </tr>

            <tr>
                <td>@Html.LabelFor(model => model.PartySize, "Party Size")</td>
                <td>@Html.DropDownListFor()</td>
                <td>@Html.ValidationMessageFor(model => model.PartySize)</td>
            </tr>

            <tr>
                <td>@Html.LabelFor(model => model.Question, "Question")</td>
                <td>@Html.TextBoxFor(model => model.Question)</td>
                <td>@Html.ValidationMessageFor(model => model.Question)</td>
            </tr>
        </table>

        <input type="submit" value="Send Enquiry" />
    </fieldset>
}

public class EnquiriesController : Controller
{
    //
    // GET: /Enquiries/

    public ActionResult Index()
    {

    }

    // POST: /Enquiries/

    [HttpPost]
    public ActionResult Index(EnquiryForm enquiryForm)
    {
        if (ModelState.IsValid)
        {

        }

        return View(enquiryForm);
    }
}

---

创建一个名为

public class KeyValuePair 
{
  public string Text;
  public string Text;
}

在获取索引操作中

List<KeyValuePair> keyValuePair = new List<KeyValuePair>(); //Add your drop down values into this list
ViewBag.PartySize= new SelectList(keyValuePair, "Value", "Text", selectedValue: id);

List keyValuePair=new List（）//将下拉列表中的值添加到此列表中
ViewBag.PartySize=新的选择列表（keyValuePair，“值”，“文本”，selectedValue:id）；

在查看页面上

<td>@Html.LabelFor(model => model.PartySize, "Party Size")</td>
<td>@Html.DropDownList("PartySize",(SelectList)ViewBag.PartySize)</td>
<td>@Html.ValidationMessageFor(model => model.PartySize)</td>

@Html.LabelFor（model=>model.PartySize，“Party Size”）
@Html.DropDownList（“PartySize”，（SelectList）ViewBag.PartySize）
@Html.ValidationMessageFor（model=>model.PartySize）

首先，您需要向ViewModel添加PartySize属性：

public int PartySize { get; set; }

然后，在控制器中，您将拥有：

public ActionResult Index()
{
    var model = new EnquiryForm();

    ViewBag.PartySizes = Enumearable.Range(1, 8);
    return View(model);
}

<tr>
    <td>@Html.LabelFor(model => model.PartySize, "Party Size")</td>
    <td>@Html.DropDownListFor(model => model.PartySize, new SelectList(ViewBag.PartySizes))</td>
    <td>@Html.ValidationMessageFor(model => model.PartySize)</td>
</tr>

在您看来，您将拥有：

public ActionResult Index()
{
    var model = new EnquiryForm();

    ViewBag.PartySizes = Enumearable.Range(1, 8);
    return View(model);
}

<tr>
    <td>@Html.LabelFor(model => model.PartySize, "Party Size")</td>
    <td>@Html.DropDownListFor(model => model.PartySize, new SelectList(ViewBag.PartySizes))</td>
    <td>@Html.ValidationMessageFor(model => model.PartySize)</td>
</tr>

@Html.LabelFor（model=>model.PartySize，“Party Size”）
@Html.DropDownListFor（model=>model.PartySize，新选择列表（ViewBag.PartySizes））
@Html.ValidationMessageFor（model=>model.PartySize）

我通过一个

ViewBag

来实现这一点，但我将

SelectList

实例化代码保留在控制器中的适当位置。这里有一个例子；我希望这有助于：

在视图中

@Html.DropDownListFor(model => model.PartySize, ViewBag.Sizes as SelectList, "Party Size")

视图模型（添加）

在控制器中

List<int> Sizes = new List<int>();

        for(int i = 1; i < 9; i++)
        {
            Sizes.Add(i);
        }

        ViewBag.Sizes = new SelectList(Sizes);

列表大小=新列表（）；
对于（int i=1；i<9；i++）
{
增加（i）；
}
ViewBag.size=新选择列表（尺寸）；

无需创建

KeyValuePair

类。