System.Web.UI.WebControls

1. using System;  
2. using System.Collections.Generic;  
3. using System.Linq;  
4. using System.Web;  
5. using System.Web.UI;    http://www.gitom.com/973631
6. using System.Web.UI.WebControls;  
7. using System.Data.SqlClient;  
8. using System.Data;  
9. namespace 省市联动  
10. {  
11.     public partial class 省市联动 : System.Web.UI.Page  
12.     {  
13.         string strCon = "server=.;database=Place;uid=sa;pwd=123456";  
14.         protected void Page_Load(object sender, EventArgs e)  
15.         {  
16.             //DropDownList1.Text = "北京市";  
17.             if (!IsPostBack)  
18.             {  
19.                 SqlConnection sqlcon = new SqlConnection(strCon);  
20.                 string sqlstr = "select * from Province";  
21.                 string strCity = "select * from City where Province = '北京市'";  
22.                 SqlDataAdapter myda = new SqlDataAdapter(sqlstr, strCon);  
23.                 SqlDataAdapter mydaCity = new SqlDataAdapter(strCity, sqlcon);  
24.                 DataSet myds = new DataSet();  
25.                 DataSet mydsCity = new DataSet();  
26.                 sqlcon.Open();  
27.                 myda.Fill(myds);  
28.                 mydaCity.Fill(mydsCity);  
29.                 DropDownList1.DataSource = myds;  
30.                 DropDownList1.DataValueField = "ProvinceName";  
31.                 DropDownList1.DataBind();  
32.                 DropDownList2.DataSource = mydsCity;  
33.                 DropDownList2.DataValueField = "CityName";  
34.                 DropDownList2.DataBind();  
35.                 sqlcon.Close();  
36.             }  
37.         }  
38.         protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)  
39.         {  
40.             SqlConnection sqlcon = new SqlConnection(strCon);  
41.             string sqlstr = "select * from City where Province = '" + DropDownList1.SelectedValue.Trim() + "'";  
42.             SqlDataAdapter myda = new SqlDataAdapter(sqlstr, sqlcon);  
43.             DataSet myds = new DataSet();  
44.             sqlcon.Open();  
45.             myda.Fill(myds);  
46.             DropDownList2.DataSource = myds;  
47.             DropDownList2.DataValueField = "CityName";  
48.             DropDownList2.DataBind();  
49.             sqlcon.Close();  http://www.gitom.com/973631
50.         }