SQL數據庫代碼:
create database proCity
use proCity
create table province(
proId int primary key,
proName varchar(20) not null
)
use proCity
insert into province values(1,'江西')
insert into province values(2,'湖南')
insert into province values(3,'湖北')
select * from province
use proCity
create table city(
cityId int primary key,
proId int foreign key references province(proId),
cityName varchar(10)
)
use proCity
insert into city values
('1','1','南昌'),('2','1','九江'),('3','1','新餘'),
('4','2','長沙'),('5','2','株洲'),('6','2','湘潭'),
('7','3','武漢'),('8','3','荊州'),('9','3','宜昌')
select * from city
前臺代碼:
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="WebApplication2.WebForm1" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
省份：
<asp:DropDownList ID="dropDownList1" runat="server" AutoPostBack="True"
onselectedindexchanged="dropDownList1_SelectedIndexChanged"></asp:DropDownList><br /><br />
城市：
<asp:DropDownList ID="dropDownList2" runat="server"></asp:DropDownList>
</div>
</form>
</body>
</html>
數據庫連接類代碼:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data.SqlClient;
namespace WebApplication2
{
public class DB
{
public static SqlConnection sqlcon()
{
return new SqlConnection("server=.;database=proCity;uid=sa;pwd=123456");
}
}
}
後臺代碼:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data.SqlClient;
namespace WebApplication2
{
public partial class WebForm1 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
//在網頁第一次打開的時候進行調用
if (!IsPostBack)
{
this.dataBind();
}
}
protected void dataBind()
{
SqlConnection sqlcon = DB.sqlcon();
sqlcon.Open();
SqlCommand sqlcom = new SqlCommand("select * from province", sqlcon);
SqlDataReader dr = sqlcom.ExecuteReader();
this.dropDownList1.DataSource = dr;
this.dropDownList1.DataValueField = "proId";
this.dropDownList1.DataTextField = "proName";
this.dropDownList1.DataBind();
dr.Close();
sqlcom.CommandText = "select * from city";
SqlDataReader dr1 = sqlcom.ExecuteReader();
this.dropDownList2.DataSource = dr1;
this.dropDownList2.DataValueField = "cityId";
this.dropDownList2.DataTextField = "cityName";
this.dropDownList2.DataBind();
dr1.Close();
sqlcon.Close();
}
protected void dropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
int proID = Convert.ToInt32(this.dropDownList1.SelectedItem.Value);
SqlConnection sqlcon = DB.sqlcon();
sqlcon.Open();
SqlCommand sqlcom = new SqlCommand("select * from city where proId= ' " + proID + " '", sqlcon);
SqlDataReader dr = sqlcom.ExecuteReader();
this.dropDownList2.DataSource = dr;
this.dropDownList2.DataValueField = "cityId";
this.dropDownList2.DataTextField = "cityName";
this.dropDownList2.DataBind();
dr.Close();
sqlcon.Close();
}
}
}