using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace WebApplication4
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            int i;
        }

        protected void VehicleList_SelectedIndexChanged(object sender, EventArgs e)
        {
            //SelectedItemList.Items.Clear();
            //SelectedItemList.Visible = false;
            switch (VehicleList.SelectedValue)
            {
                case "Car":
                    string[] cars = {"BMW", "MercedesBenz", "Audi"};
                    SelectedItemList.DataSource = cars;
                    break;
                case "Airplane":
                    string[] airplane = { "Boeing", "Airbus"};
                    SelectedItemList.DataSource = airplane;
                    break;
                case "Train":
                    string[] trains = {"Ghan", "TransSiberian"};
                    SelectedItemList.DataSource = trains;
                    break;
                default:
                    SelectedItemList.Visible = false;
                    break;
            }
            if(SelectedItemList.DataSource == null){
                SelectedItemList.Visible = true;
            }
            SelectedItemList.DataBind();

        }

        protected void PrintButton_OnClick(object sender, EventArgs e)
        {
            Response.Write(VehicleList.SelectedValue + ": " + SelectedItemList.SelectedValue);
        }
    }
}