I have doubt, how to populate one dropdown list box details to other in c#.net

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace _26196_filtering_collections_in_c_sharp
{
    public partial class Form1 : Form
    {
        public static List<CarModel> lstCarModel = new List<CarModel>();
        public Form1()
        {
            InitializeComponent();

            lstCarModel.Add(new CarModel("MARUTHI", "800"));
            lstCarModel.Add(new CarModel("FORD", "FIGO"));

            this.comboBox1.DataSource = lstCarModel;
            this.comboBox1.DisplayMember = "Car";
            this.comboBox1.ValueMember = "Car";
        }

        private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            
            List<CarModel> FilteredCarModel = lstCarModel;
            var filtered = from CarModel cm in lstCarModel
                           where cm.Car == comboBox1.Text.ToString()
                           select cm;
            this.comboBox2.Items.Clear();
    

            foreach (CarModel carmodel in filtered)
            {
                this.comboBox2.Items.Add(carmodel.Model.ToString());
            }
           
        }

        public class CarModel
        {
            string car;
            public string Car{get { return car; }}
            string model;
            public string Model{get { return model; }}
            public CarModel(string car, string model){this.car= car;this.model= model;}
            public override string ToString(){return string.Format("{0}: {1}", car, model);}
        }
    }
}

public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        Person p1 = new Person { Id = "A", Name = "Kayes", Age = 29, JoiningDate = DateTime.Parse("2010-06-06") };
        Person p2 = new Person { Id = "B", Name = "Gibbs", Age = 34, JoiningDate = DateTime.Parse("2008-04-23") };
        Person p3 = new Person { Id = "C", Name = "Steyn", Age = 28, JoiningDate = DateTime.Parse("2011-02-17") };

        List<person> persons = new List<person>();
        persons.Add(p1);
        persons.Add(p2);
        persons.Add(p3);

       ExampleDDL.DataTextField = "Name";
        ExampleDDL.DataValueField = "Id";

        ExampleDDL.DataSource = persons;
        ExampleDDL.DataBind();
    }
}

public class Person
{
    public string Id { get; set; }
    public string Name { get; set; }
    public int Age { get; set; }
    public DateTime JoiningDate { get; set; }
}