【ASP.NET】 MVC下拉框联动

这个case主要是我在做项目的时候遇到一个需要根据input控件输入的内容，动态填充dropdown list中的内容， 实现二者联动的需求。在搜索了一些资源后，这篇博客解决了我的问题，所以记录并转载一下。

转载自： https://www.jb51.net/article/88986.htm

数据库schema：

USE master
GO
IF EXISTS (SELECT * FROM sysdatabases WHERE name='MyAddressDB' )
DROP DATABASE MyAddressDB
GO
CREATE DATABASE MyAddressDB
GO
USE MyAddressDB
GO 

IF EXISTS (SELECT * FROM sysobjects WHERE name='Province')
DROP TABLE Province
GO
--省份表
CREATE TABLE Province
(
ProvinceID INT IDENTITY(1,1) PRIMARY KEY,
ProvinceName NVARCHAR(50) NOT NULL
)

IF EXISTS (SELECT * FROM sysobjects WHERE name='City')
DROP TABLE City
GO
--省份表
CREATE TABLE City
(
CityID INT IDENTITY(1,1) PRIMARY KEY,
CityName NVARCHAR(50) NOT NULL,
ProvinceID INT REFERENCES dbo.Province(ProvinceID) NOT NULL
)

--插入测试语句：【在网上找了一个省市数据库，把里面的数据导入我当前数据库中】
--开始
INSERT INTO dbo.Province
SELECT ProvinceName FROM Temp.dbo.S_Province

INSERT INTO dbo.City
 ( CityName, ProvinceID )
 SELECT CityName, ProvinceID FROM Temp.dbo.S_City
--结束

--测试插入成功与否
--SELECT * FROM dbo.Province
--SELECT * FROM dbo.City

Model代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace JsonDataInMVC.Models
{
 public class Province
 {
 public int ProvinceID { get; set; }

 public string ProvinceName { get; set; }
 }
} 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace JsonDataInMVC.Models
{
 public class City
 {
 public int CityID { get; set; }

 public string CityName { get; set; }

 public int ProvinceID { get; set; }

 }
}

DB Operator：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Configuration;
using JsonDataInMVC.Models;
using System.Data;
using System.Data.SqlClient;

namespace JsonDataInMVC.DBOperator
{
 public class AddressHelper
 {

 /// <summary>
 /// 连接字符串
 /// </summary>
 public string ConnectionString
 {
  get
  {
  return ConfigurationManager.ConnectionStrings["DBConnectionString"].ConnectionString;
  }
 }

 /// <summary>
 /// 获取所有的省份
 /// </summary>
 /// <returns></returns>
 public List<Province> GetAllProvince()
 {
  List<Province> lstProvince = new List<Province>();
  string sql = @"SELECT * FROM dbo.Province";

  //ADO.NET连接方式访问数据库
  //1.创建连接对象[连接字符串]
  SqlConnection conn = new SqlConnection(ConnectionString);

  //2.创建命令对象
  SqlCommand cmd = new SqlCommand();
  cmd.CommandText = sql;
  cmd.CommandType = CommandType.Text;
  cmd.Connection = conn;

  //3.打开连接
  conn.Open();

  //4.发送命令
  SqlDataReader reader= cmd.ExecuteReader();

  //5.处理数据
  while (reader.Read())
  {
  lstProvince.Add(new Province()
  {

   ProvinceID =Convert.ToInt32( reader["ProvinceID"]),
   ProvinceName = reader["ProvinceName"].ToString()
  });
  }

  //6.关闭连接
  conn.Close();
  reader.Close();

  return lstProvince;

 }

 /// <summary>
 /// 通过ProvinceID获取市的数据
 /// </summary>
 /// <param name="id"></param>
 /// <returns></returns>
 public List<City> GetCityListByProvinceID(int id)
 {
  DataSet ds = new DataSet();
string sql = @"SELECT CityID,CityName FROM dbo.City WHERE ProvinceID=@ProvinceID";

  //ADO.NET非连接方式访问数据库

  //1.创建连接对象
  SqlConnection conn = new SqlConnection(ConnectionString);
　　　　　　　　//2.创建数据适配器对象
 　　　　　　　　 SqlDataAdapter sda = new SqlDataAdapter(sql,conn);//这里还真必须这样写。不能像下面的两条注释语句那样写。
 　　　　　　　　//sda.SelectCommand.Connection = conn;
　　　　　　　　//sda.SelectCommand.CommandText = sql;
　　　　　　　　 sda.SelectCommand.CommandType = CommandType.Text;
  sda.SelectCommand.Parameters.AddWithValue("@ProvinceID", id);//参数设置别忘了
  //3.打开连接【注意，非链接模式下，连接的打开关闭，无所谓，不过还是打开好点。规范化】
  conn.Open();

  //4.发送命令
  sda.Fill(ds);

  //5.处理数据

  //6关闭连接【【注意，非链接模式下，连接的打开关闭，无所谓，不过还是打开好点。规范化】】
  conn.Close();

  return DataTableToList<City>.ConvertToModel(ds.Tables[0]).ToList<City>();
 }
 }
}

DB转list

using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Reflection;
using System.Web;

namespace JsonDataInMVC.DBOperator
{
 public static class DataTableToList<T> where T : new()
 {
 public static IList<T> ConvertToModel(DataTable dt)
 {
  //定义集合
  IList<T> ts = new List<T>();
  T t = new T();
  string tempName = "";
  //获取此模型的公共属性
  PropertyInfo[] propertys = t.GetType().GetProperties();
  foreach (DataRow row in dt.Rows)
  {
  t = new T();
  foreach (PropertyInfo pi in propertys)
  {
   tempName = pi.Name;
   //检查DataTable是否包含此列
   if (dt.Columns.Contains(tempName))
   {
   //判断此属性是否有set
   if (!pi.CanWrite)
    continue;
   object value = row[tempName];
   if (value != DBNull.Value)
    pi.SetValue(t, value, null);
   }
  }
  ts.Add(t);
  }
  return ts;
 }
 }
}

controller：

using JsonDataInMVC.DBOperator;
using JsonDataInMVC.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace JsonDataInMVC.Controllers
{
 public class ProvinceController : Controller
 {
 private AddressHelper db;
 public ProvinceController()
 {
  db = new AddressHelper();
 }
 // GET: Province
 public ActionResult Index()
 {
  List<Province> lstProvince= db.GetAllProvince();

  ViewBag.ListProvince = lstProvince;

  return View();
 }

 public JsonResult GetAllCityByProvinceID(int id)
 {
  List<City> lstCity= db.GetCityListByProvinceID(id);
  return Json(lstCity, JsonRequestBehavior.AllowGet);
 }
 }
}

View：

@using JsonDataInMVC.Models
@{
 ViewBag.Title = "Index";
 List<Province> lstProvince = ViewBag.ListProvince as List<Province>;
}

<h2>ProvinceIndex</h2>

<label>省份:</label>
<select id="myProvince">
 @foreach (var item in lstProvince)
 {
 <option value="@item.ProvinceID">@item.ProvinceName</option>
 }
</select>
<br/>
<hr />
<label>城市:</label>
<select id="myCity">

</select>
<script src="~/Scripts/jquery-1.10.2.js"></script>
<script type="text/javascript">
 $(document).ready(function () {
 $("#myProvince").change(function () {
  //获取省份的ID
  var provinceID = $("#myProvince").val();

  //获取城市
  var myCity=$("#myCity");

  //加入测试代码
  debugger;

  $.ajax({
  url: "/Province/GetAllCityByProvinceID/" + provinceID,
  type: "post",
  dataType: "json",
  contentType: "application/json",
  success: function (result) {
   var myHTML = "";
   myCity.html("");//赋值之前先清空
   $.each(result, function (i, data) {
   myHTML += "<option value=" + data.CityID + ">" + data.CityName + "</option>";

   });
   myCity.append(myHTML);
  },
  error: function (result) {
   alert(result.responseText);
  }

  });

 })

 })
</script>

Route：

public static void RegisterRoutes(RouteCollection routes)
{
 routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

 routes.MapRoute(
 name: "Default",
 url: "{controller}/{action}/{id}",
 defaults: new { controller = "Province", action = "Index", id = UrlParameter.Optional }
 );
}