MVC实现多选下拉框

借助Chosen Plugin可以实现多选下拉框。

 

选择多项：

 

设置选项数量，比如设置最多允许2个选项：

 

考虑到多选下拉<select multiple="multiple"...></select>选中项是string数组，Model应该这样设计：

using System.Collections.Generic;

using System.Web.Mvc;



namespace MvcApplication1.Models

{

    public class CarVm

    { 

        public string[] SelectedCars { get; set; }

        public IEnumerable<SelectListItem>  AllCars { get; set; }

    }

}

 

HomeController中：

using System.Collections.Generic;

using System.Linq;

using System.Web.Mvc;

using MvcApplication1.Models;



namespace MvcApplication1.Controllers

{

    public class HomeController : Controller

    {

        public ActionResult Index()

        {

            CarVm carVm = new CarVm();

            carVm.SelectedCars = new string[]{"1","2"};

            carVm.AllCars = GetAllCars();

            return View(carVm);

        }



        [HttpPost]

        public ActionResult SaveCars(CarVm carVm)

        {

            if (ModelState.IsValid)

            {

                return View(carVm);

            }

            return RedirectToAction("Index", carVm);

        }



        private IEnumerable<SelectListItem> GetAllCars()

        {

            List<SelectListItem> allCars = new List<SelectListItem>();

            allCars.Add(new SelectListItem() {Value = "1",Text = "奔驰"});

            allCars.Add(new SelectListItem() { Value = "2", Text = "宝马" });

            allCars.Add(new SelectListItem() { Value = "3", Text = "奇瑞" });

            allCars.Add(new SelectListItem() { Value = "4", Text = "比亚迪" });

            allCars.Add(new SelectListItem() { Value = "5", Text = "起亚" });

            allCars.Add(new SelectListItem() { Value = "6", Text = "大众" });

            allCars.Add(new SelectListItem() { Value = "7", Text = "斯柯达" });

            allCars.Add(new SelectListItem() { Value = "8", Text = "丰田" });

            allCars.Add(new SelectListItem() { Value = "9", Text = "本田" });



            return allCars.AsEnumerable();

        }

    }

}

Home/Index.cshtml视图中，需要引用Chosen Plugin的css和js文件：

@model MvcApplication1.Models.CarVm



@{

    ViewBag.Title = "Index";

    Layout = "~/Views/Shared/_Layout.cshtml";

}



<h2>Index</h2>

<link href="~/Content/chosen.css" rel="stylesheet" />



@using (Html.BeginForm("SaveCars", "Home", FormMethod.Post))

{

    @Html.LabelFor(m => m.SelectedCars,"最多选择2个选项") <br/>

    @Html.ListBoxFor(m => m.SelectedCars, Model.AllCars, new {@class="chosen", multiple="multiple", style="width:350px;"}) <br/>

    <input type="submit" value="提交"/>

}





@section scripts

{

    <script src="~/Scripts/chosen.jquery.min.js"></script>

    <script type="text/javascript">

        $(function() {

            $('.chosen').chosen({

                max_selected_options: 2

            });



            $(".chosen-deselect").chosen(

            {

                allow_single_deselect: true 

            });



            $(".chosen").chosen().change();

            $(".chosen").trigger('liszt:updated');

        });

    </script>

}