ASP.NET实现级联下拉框效果实例讲解_实用技巧_

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>

 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; public partial class _Default : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { if (!this.IsPostBack) { SqlConnection con = DBCon.createConnection(); con.Open(); //显示部门 SqlCommand cmd = new SqlCommand("select * from Tdepartment", con); SqlDataReader sdr = cmd.ExecuteReader(); this.ddlDep.DataSource = sdr; this.ddlDep.DataTextField = "depName"; this.ddlDep.DataValueField = "depID"; this.ddlDep.DataBind(); sdr.Close(); //显示员工 SqlCommand cmdEmp =new SqlCommand ("select * from emp where depID=" + this.ddlDep .SelectedValue ,con); SqlDataReader sdrEmp = cmdEmp.ExecuteReader(); while (sdrEmp.Read()) { this.lBoxEmp.Items.Add (new ListItem(sdrEmp.GetString(1),sdrEmp .GetInt32 (0).ToString ())); } sdrEmp.Close(); //关闭连接 con.Close(); } } protected void ddlDep_SelectedIndexChanged(object sender, EventArgs e) { this.lBoxEmp.Items.Clear(); SqlConnection con = DBCon.createConnection(); con.Open(); SqlCommand cmdEmp = new SqlCommand("select * from emp where depID=" + this.ddlDep.SelectedValue, con); SqlDataReader sdrEmp = cmdEmp.ExecuteReader(); while (sdrEmp.Read()) { this.lBoxEmp.Items.Add(new ListItem(sdrEmp.GetString(1), sdrEmp.GetInt32(0).ToString())); } sdrEmp.Close(); //关闭连接 con.Close(); } } 

 using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Data.SqlClient; /// 
 /// DBCon 的摘要说明 /// 
 public class DBCon { public DBCon() { // // TODO: 在此处添加构造函数逻辑 // } public static SqlConnection createConnection() { SqlConnection con = new SqlConnection("server=.;database=department;uid=sa;pwd=123456"); return con; } }