MVC4中使用Html.DropDownList实现级联

准备工作

首先准备一下要级联的数据，新建两个类：Province和City

    public class Province
    {
        public string Id { get; set; } public string Name { get; set; } } public class City { public string Id { get; set; } public string Name { get; set; } public string Province { get; set; } }

并在Controller中准备好数据，

        List<Province> provinceList = new List<Province>();
        List<City> cityList = new List<City>();

        private void InitData() { provinceList.Add(new Province { Id = "1", Name = "河北省" }); provinceList.Add(new Province { Id = "2", Name = "河南省" }); provinceList.Add(new Province { Id = "3", Name = "广东省" }); cityList.Add(new City { Id = "11", Name = "石家庄", Province = "1" }); cityList.Add(new City { Id = "12", Name = "邢台", Province = "1" }); cityList.Add(new City { Id = "13", Name = "保定", Province = "1" }); cityList.Add(new City { Id = "21", Name = "郑州", Province = "2" }); cityList.Add(new City { Id = "22", Name = "安阳", Province = "2" }); cityList.Add(new City { Id = "23", Name = "洛阳", Province = "2" }); cityList.Add(new City { Id = "31", Name = "广州", Province = "3" }); cityList.Add(new City { Id = "32", Name = "中山", Province = "3" }); cityList.Add(new City { Id = "33", Name = "佛山", Province = "3" }); }

Controller

在控制器中创建一个返回分步视图的Action，在前台第一级调用的时候触发这个action，返回第二级需要的数据。

        public ActionResult ShowCity(string provinceId)
        {
            InitData();
            var result = cityList.Where(city => city.Province == provinceId);
            ViewBag.City = result; return PartialView("PartialCity"); }

View

先创建一个PartialView：PartialCity.cshtml，如下：

@{
    ViewBag.Title = "PartialCity";
}


城市: @Html.DropDownList("city_dropdownlist", new SelectList(ViewBag.City, "Id", "Name"))

在主View中的使用这个PartialView，

    <div id="province">
        省份: @Html.DropDownList("province_dropdownlist", new SelectList(ViewBag.Province, "Id", "Name")) </div> <div id="city"> @Html.Partial("PartialCity") </div>

最后，需要在主View页面写几行js代码，给第一级dropdownlist注册一个change事件，并且在事件触发的时候调用刚刚创建的ShowCity方法

@Scripts.Render("~/Scripts/jquery-1.7.1.min.js");
<script type="text/javascript"> $(document).ready(init); function init() { $("select[name='province_dropdownlist']").change(function () { var selectedProvince = $(this).val(); ShowCityWithSelectedProvince(selectedProvince); }); } function ShowCityWithSelectedProvince(province) { $.ajax({ url: "@Url.Action("ShowCity", "Home")", data: { provinceId: province }, success: function (data) { $("#city").html(data); } }); }

这样，就实现了级联效果。

以上