MVC4中使用Html.DropDownList实现级联

本文记录了一个在MVC4中使用PartialView实现级联效果的小例子。

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