如何在MVC中的Controller中获取DropDownList SelectedValue

Question

我有下拉列表,我已从数据库中填写.现在我需要在Controller中获取所选值进行一些操作.但没有得到这个想法.我试过的代码.

模型

public class MobileViewModel 
{          
    public List<tbInsertMobile> MobileList;
    public SelectList Vendor { get; set; }
}

调节器

 public ActionResult ShowAllMobileDetails()
    {
        MobileViewModel MV = new MobileViewModel();
        MV.MobileList = db.Usp_InsertUpdateDelete(null, "", "", null, "", 4, MergeOption.AppendOnly).ToList();
        MV.Vendor = new SelectList(db.Usp_VendorList(), "VendorId", "VendorName");
        return View(MV);
    }

    [HttpPost]
    public ActionResult ShowAllMobileDetails(MobileViewModel MV)
    {           
        string strDDLValue = ""; // Here i need the dropdownlist value

        return View(MV);
    }

视图

   <table>           
        <tr>
            <td>Mobile Manufacured</td>
            <td>@Html.DropDownList("ddlVendor", Model.Vendor, "Select Manufacurer") </td>
        </tr>         
        <tr>
            <td>

            </td>
            <td>
                <input id="Submit1" type="submit" value="search" />
            </td>
        </tr>
    </table>

Answer 1

第一种方法(通过Request或FormCollection):

您可以从Request使用中读取它Request.Form,您的下拉名称是formCollection中的ddlVendorpass ddlVendor密钥,以获取由表单发布的值:

string strDDLValue = Request.Form["ddlVendor"].ToString();

或使用FormCollection:

[HttpPost]
public ActionResult ShowAllMobileDetails(MobileViewModel MV,FormCollection form)
{           
  string strDDLValue = form["ddlVendor"].ToString();

  return View(MV);
}

第二种方法(通过型号):

如果你想使用模型绑定,那么在Model中添加一个属性:

public class MobileViewModel 
{          
    public List<tbInsertMobile> MobileList;
    public SelectList Vendor { get; set; }
    public string SelectedVendor {get;set;}
}

在视图中:

@Html.DropDownListFor(m=>m.SelectedVendor , Model.Vendor, "Select Manufacurer")

并在行动:

[HttpPost]
public ActionResult ShowAllMobileDetails(MobileViewModel MV)
{           
   string SelectedValue = MV.SelectedVendor;
   return View(MV);
}

更新:

如果您还要发布所选项目的文本,则必须在隐藏字段中添加隐藏字段和下拉选择更改集选定项目文本:

public class MobileViewModel 
{          
    public List<tbInsertMobile> MobileList;
    public SelectList Vendor { get; set; }
    public string SelectVendor {get;set;}
    public string SelectedvendorText { get; set; }
}

使用jquery设置隐藏字段:

<script type="text/javascript">
$(function(){
$("#SelectedVendor").on("change", function {
   $("#SelectedvendorText").val($(this).text());
 });
});
</script>

@Html.DropDownListFor(m=>m.SelectedVendor , Model.Vendor, "Select Manufacurer")
@Html.HiddenFor(m=>m.SelectedvendorText)

Answer 2

模型

非常基本的性别领域模型.GetGenderSelectItems()返回填充DropDownList所需的选择项.

public enum Gender 
{
    Male, Female
}

public class MyModel
{
    public Gender Gender { get; set; }

    public static IEnumerable<SelectListItem> GetGenderSelectItems()
    {
        yield return new SelectListItem { Text = "Male", Value = "Male" };
        yield return new SelectListItem { Text = "Female", Value = "Female" };
    }
}

视图

请确保您将自己包裹@Html.DropDownListFor在表格标签中.

@model MyModel

@using (Html.BeginForm("MyController", "MyAction", FormMethod.Post)
{
   @Html.DropDownListFor(m => m.Gender, MyModel.GetGenderSelectItems())
   <input type="submit" value="Send" />
}

调节器

您的.cshtml Razor视图名称应与控制器操作名称相同,文件夹名称应与控制器名称匹配,例如Views\MyController\MyAction.cshtml.

public class MyController : Controller 
{
    public ActionResult MyAction()
    {
        // shows your form when you load the page
        return View();
    }

    [HttpPost]
    public ActionResult MyAction(MyModel model)
    {
        // the value is received in the controller.
        var selectedGender = model.Gender;
        return View(model);
    }
}

走得更远

现在让我们强类型和枚举独立:

var genderSelectItems = Enum.GetValues(typeof(Gender))
    .Cast<string>()
    .Select(genderString => new SelectListItem 
    {
        Text = genderString,
        Value = genderString,
    }).AsEnumerable();

Answer 3

MVC 5/6/剃刀页面

我认为最好的方法是使用强类型模型，因为 Viewbags 已经被滥用了:)

MVC 5示例

您的获取行动

public async Task<ActionResult> Register()
    {
        var model = new RegistrationViewModel
        {
            Roles = GetRoles()
        };

        return View(model);
    }

你的视图模型

    public class RegistrationViewModel
    {
        public string Name { get; set; }

        public int? RoleId { get; set; }

        public List<SelectListItem> Roles { get; set; }
    }    

您的看法

    <div class="form-group">
        @Html.LabelFor(model => model.RoleId, htmlAttributes: new { @class = "col-form-label" })
        <div class="col-form-txt">
            @Html.DropDownListFor(model => model.RoleId, Model.Roles, "--Select Role--", new { @class = "form-control" })
            @Html.ValidationMessageFor(model => model.RoleId, "", new { @class = "text-danger" })
        </div>
    </div>                                   

您的帖子操作

    [HttpPost, ValidateAntiForgeryToken]
    public async Task<ActionResult> Register(RegistrationViewModel model)
    {
        if (ModelState.IsValid)
        {
            var _roleId = model.RoleId, 

MVC 6 会有一点不同

采取行动

public async Task<ActionResult> Register()
    {
        var _roles = new List<SelectListItem>();
        _roles.Add(new SelectListItem
        {
           Text = "Select",
           Value = ""
        });
        foreach (var role in GetRoles())
        {
          _roles.Add(new SelectListItem
          {
            Text = z.Name,
            Value = z.Id
          });
        }

        var model = new RegistrationViewModel
        {
            Roles = _roles
        };

        return View(model);
    }

您的视图模型将与 MVC 5 相同

你的视图会像

<select asp-for="RoleId" asp-items="Model.Roles"></select>

帖子也将是相同的

剃刀页面

您的页面模型

[BindProperty]
public int User User { get; set; } = 1;

public List<SelectListItem> Roles { get; set; }

public void OnGet()
{
    Roles = new List<SelectListItem> {
        new SelectListItem { Value = "1", Text = "X" },
        new SelectListItem { Value = "2", Text = "Y" },
        new SelectListItem { Value = "3", Text = "Z" },
   };
}

<select asp-for="User" asp-items="Model.Roles">
    <option value="">Select Role</option>
</select>

我希望它可以帮助别人:)