how to assign value to dropdownlist based on selection

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





   


   

   

                    onselectedindexchanged="DropDownList1_SelectedIndexChanged">
       

                    onselectedindexchanged="DropDownList2_SelectedIndexChanged">
       

                    onselectedindexchanged="DropDownList3_SelectedIndexChanged">
       

   

   

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Data.SqlClient;
namespace Dropdownlist_insert
{
    public partial class _Default : System.Web.UI.Page
    {
        string strConnString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
        string str;
        SqlCommand com;

        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                DropDownList1.Items.Add("Choose");
                DropDownList1.Items.Add("Excellent");
                DropDownList1.Items.Add("Good");
                DropDownList1.Items.Add("Fair");

                DropDownList2.Items.Add("Choose");
                DropDownList2.Items.Add("Excellent");
                DropDownList2.Items.Add("Good");
                DropDownList2.Items.Add("Fair");

                DropDownList3.Items.Add("Choose");
                DropDownList3.Items.Add("Excellent");
                DropDownList3.Items.Add("Good");
                DropDownList3.Items.Add("Fair");
            }
           
        }

        protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (DropDownList1.SelectedItem.Text == "Excellent")
            {
                SqlConnection con = new SqlConnection(strConnString);
                con.Open();
                str = "insert into employee(status) values('1')";
                com = new SqlCommand(str, con);
                com.ExecuteNonQuery();
                con.Close();
            }
            else if (DropDownList1.SelectedItem.Text == "Good")
            {
                SqlConnection con = new SqlConnection(strConnString);
                con.Open();
                str = "insert into employee(status) values('2')";
                com = new SqlCommand(str, con);
                com.ExecuteNonQuery();
                con.Close();
            }
            else
            {
                SqlConnection con = new SqlConnection(strConnString);
                con.Open();
                str = "insert into employee(status) values('3')";
                com = new SqlCommand(str, con);
                com.ExecuteNonQuery();
                con.Close();
            }
        }

        protected void DropDownList2_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (DropDownList2.SelectedItem.Text == "Excellent")
            {
                SqlConnection con = new SqlConnection(strConnString);
                con.Open();
                str = "insert into employee(status) values('1')";
                com = new SqlCommand(str, con);
                com.ExecuteNonQuery();
                con.Close();
            }
            else if (DropDownList2.SelectedItem.Text == "Good")
            {
                SqlConnection con = new SqlConnection(strConnString);
                con.Open();
                str = "insert into employee(status) values('2')";
                com = new SqlCommand(str, con);
                com.ExecuteNonQuery();
                con.Close();
            }
            else
            {
                SqlConnection con = new SqlConnection(strConnString);
                con.Open();
                str = "insert into employee(status) values('3')";
                com = new SqlCommand(str, con);
                com.ExecuteNonQuery();
                con.Close();
            }
        }

        protected void DropDownList3_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (DropDownList3.SelectedItem.Text == "Excellent")
            {
                SqlConnection con = new SqlConnection(strConnString);
                con.Open();
                str = "insert into employee(status) values('1')";
                com = new SqlCommand(str, con);
                com.ExecuteNonQuery();
                con.Close();
            }
            else if (DropDownList3.SelectedItem.Text == "Good")
            {
                SqlConnection con = new SqlConnection(strConnString);
                con.Open();
                str = "insert into employee(status) values('2')";
                com = new SqlCommand(str, con);
                com.ExecuteNonQuery();
                con.Close();
            }
            else
            {
                SqlConnection con = new SqlConnection(strConnString);
                con.Open();
                str = "insert into employee(status) values('3')";
                com = new SqlCommand(str, con);
                com.ExecuteNonQuery();
                con.Close();
            }
        }
    }
}