三级联动

Question

那位大哥有三级联动的例子，思路是和二级联动一样吗？

Answer 1

JS事件控制DIV显示，或者CSS属性和内容

Answer 2

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;public partial class _Default : System.Web.UI.Page 
{
  protected void Page_Load(object sender, EventArgs e)
  {
  if (!this.IsPostBack)
  {
  //绑定省
  SqlConnection con = new SqlConnection("server=.;database=dropDownTest;integrated security=true;");
  con.Open();
  SqlCommand cmd = new SqlCommand("select * from provience", con);
  SqlDataReader sdr = cmd.ExecuteReader();
  this.ddlprovince.DataSource = sdr;
  this.ddlprovince.DataTextField = "proName";
  this.ddlprovince.DataValueField = "proID";
  this.ddlprovince.DataBind();
  sdr.Close();
  //绑定市
  SqlCommand cmdcity = new SqlCommand("select * from city where proID=" + this.ddlprovince.SelectedValue, con);
  SqlDataReader sdr1 = cmdcity.ExecuteReader();
  this.ddlcity.DataSource = sdr1;
  this.ddlcity.DataTextField = "cityName";
  this.ddlcity.DataValueField = "cityID";
  this.ddlcity.DataBind();
  sdr1.Close();
  con.Close();
  }
     }
  protected void ddlprovince_SelectedIndexChanged(object sender, EventArgs e)
  {
  string proID = this.ddlprovince.SelectedValue;
  SqlConnection con = new SqlConnection("server=.;database=dropDownTest;integrated security=true;");
  con.Open();
  SqlCommand cmd = new SqlCommand("select*from city where proID=" + proID, con);
  SqlDataReader sdr= cmd.ExecuteReader();
  this.ddlcity.DataSource = sdr;
  this.ddlcity.DataTextField = "cityName";
  this.ddlcity.DataValueField = "cityID";
  this.ddlcity.DataBind();
  sdr.Close();
  con.Close();  }
}
ddlprovince 为省 dropdownlist IDddlcity 为市 dropdownlist IDproName proID为表provience中的字段 也就是省的cityName cityID为市city表中的字段 是市的
ddlprovince_SelectedIndexChanged为省的dropdownlist 选中事件 触发绑定 数据库 Demo 完整
DropDownList控件实现三级联动视频