Cascading Dropdownlist Using UpdatePanel

Cascading Dropdownlist Using UpdatePanel:

.aspx code:

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default2.aspx.cs" Inherits="Default2" %>





   
   
   


   

   
   
   

       
           
                                    onselectedindexchanged="DropDownList1_SelectedIndexChanged">
               
               

               

                                    onselectedindexchanged="DropDownList2_SelectedIndexChanged">
               
               

               

                                    onselectedindexchanged="DropDownList3_SelectedIndexChanged">
               

           
       
   

   

.cs file:

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.Data;
using System.Configuration;

public partial class Default2 : System.Web.UI.Page
{
    public SqlConnection conn = new SqlConnection(ConfigurationManager.AppSettings["ArtSQLConnStr"]);
    DataSet dataSet1 = new DataSet();
    SqlDataAdapter da = null;
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack)
        {
            da = new SqlDataAdapter("select * from student_test", conn);
            da.Fill(dataSet1);
            DropDownList1.DataSource = dataSet1;
            DropDownList1.DataTextField = "Test_toppic";
            DropDownList1.DataValueField = "Testid";
            DropDownList1.DataBind();
            DropDownList1.Items.Insert(0, new ListItem("Please select", "0"));
        }
    }
    protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
    {
        da = new SqlDataAdapter("select * from student_test", conn);
        da.Fill(dataSet1);
        DropDownList2.DataSource = dataSet1;
        DropDownList2.DataTextField = "Test_toppic";
        DropDownList2.DataValueField = "Testid";
        DropDownList2.DataBind();
        DropDownList2.Items.Insert(0, new ListItem("Please select", "0"));
        ScriptManager.RegisterStartupScript(UpdatePanel1, UpdatePanel1.GetType(), "Message", "", false);
    }
    protected void DropDownList2_SelectedIndexChanged(object sender, EventArgs e)
    {
        da = new SqlDataAdapter("select * from student_test", conn);
        da.Fill(dataSet1);
        DropDownList3.DataSource = dataSet1;
        DropDownList3.DataTextField = "Test_toppic";
        DropDownList3.DataValueField = "Testid";
        DropDownList3.DataBind();
        DropDownList3.Items.Insert(0, new ListItem("Please select", "0"));
        ScriptManager.RegisterStartupScript(UpdatePanel1, UpdatePanel1.GetType(), "Message", "", false);
    }
    protected void DropDownList3_SelectedIndexChanged(object sender, EventArgs e)
    {
        ScriptManager.RegisterStartupScript(UpdatePanel1, UpdatePanel1.GetType(), "Message", "", false);

    }
}


JQuery code:

$(document).ready(function () {
    EnableDisableDropdownlist();
})

function EnableDisableDropdownlist()
{
    if ($("[ID$='DropDownList1']").val() == "0")
    {
        $("[ID$='DropDownList2']").attr("disabled", true);
        $("[ID$='DropDownList3']").attr("disabled", true);
    }
    else if ($("[ID$='DropDownList2']").val() == "0")
    {
        $("[ID$='DropDownList3']").attr("disabled", true);
    }
}