全國省市數據庫的引用來自網上查詢，故省略建立數據庫的過程。參考：http://www.programfan.com/blog/article.asp?id=28128
頁面建立：(*.aspx)
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="ShengShi_Default" %>
<!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>全國省市</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:DropDownList ID="Pddl" runat="server" AutoPostBack="True" Height="35px"
onselectedindexchanged="Pddl_SelectedIndexChanged" Width="165px">
<asp:ListItem>未選擇</asp:ListItem>
</asp:DropDownList>
<asp:DropDownList ID="Cddl" runat="server" Height="35px" Width="165px">
<asp:ListItem>未選擇</asp:ListItem>
</asp:DropDownList>
</div>
</form>
</body>
</html>
後臺代碼：（*.aspx.cs）
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;
using System.Configuration;
public partial class ShengShi_Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)//只是初次加載頁面的時候才執行下面代碼。
{
string sqlcon = ConfigurationManager.ConnectionStrings["ProDBConn"].ConnectionString;//通過配置web.config文件，獲得連接字符串：<add name="ProDBConn" connectionString="Data Source=ZJK-PC;Initial Catalog=ProvincesDB;;User ID=sa;Password=123456" providerName="System.Data.SqlClient"/>，引用using System.Configuration;
using (SqlConnection conn = new SqlConnection(sqlcon))
{
conn.Open();
using (SqlCommand cmd = conn.CreateCommand())
{
cmd.CommandText = "select * from promary";
using (SqlDataReader datareader = cmd.ExecuteReader())
{
while (datareader.Read())//讀取數據庫的proName
{
string proName = datareader.GetString(datareader.GetOrdinal("proName"));
Pddl.Items.Add(proName);
}
}
}
}
}
}
private void Sqlfun(int id)//通過傳入的proID，向DropDownList添加項
{
string sqlcon = ConfigurationManager.ConnectionStrings["ProDBConn"].ConnectionString;
using (SqlConnection conn = new SqlConnection(sqlcon))
{
conn.Open();
using (SqlCommand cmd = conn.CreateCommand())
{
cmd.CommandText = "select * from city where proID=@proId order by cityID";
cmd.Parameters.Add(new SqlParameter("proId",id));
using (SqlDataReader datareader = cmd.ExecuteReader())
{
while (datareader.Read())
{
string proName = datareader.GetString(datareader.GetOrdinal("cityName"));
Cddl.Items.Add(proName);
}
}
}
}
}
protected void Pddl_SelectedIndexChanged(object sender, EventArgs e)
{
Cddl.Items.Clear();
string proName = Pddl.SelectedItem.Text;
string sqlcon = ConfigurationManager.ConnectionStrings["ProDBConn"].ConnectionString;
using (SqlConnection conn = new SqlConnection(sqlcon))
{
conn.Open();
using (SqlCommand cmd = conn.CreateCommand())
{
cmd.CommandText = "select * from promary where proName=@proName";
cmd.Parameters.Add(new SqlParameter("proName", proName));
using (SqlDataReader datareader = cmd.ExecuteReader())
{
while (datareader.Read())
{
int proId = datareader.GetInt32(datareader.GetOrdinal("proID"));
Sqlfun(proId);
}
}
}
}
}
}效果圖如下：
