Implement Cascading ( Country State City ) DropDownLists in DataList control using ASP.Net

Using the database from here Cascading DropDownList for country/State/City in ASP.Net. I have created a sample

    <asp:DataList ID="DataList1" runat="server" OnItemDataBound="OnItemDataBound">
        <ItemTemplate>
            <table>
                <tr>
                    <td>
                        Country:
                    </td>
                    <td>
                        &nbsp;
                    </td>
                    <td>
                        <asp:DropDownList ID="ddlCountries" runat="server" AutoPostBack="true" OnSelectedIndexChanged="Country_Changed">
                        </asp:DropDownList>
                    </td>
                    <td>
                        State:
                    </td>
                    <td>
                        &nbsp;
                    </td>
                    <td>
                        <asp:DropDownList ID="ddlStates" runat="server" AutoPostBack="true" OnSelectedIndexChanged="State_Changed">
                        </asp:DropDownList>
                    </td>
                    <td>
                        City:
                    </td>
                    <td>
                        &nbsp;
                    </td>
                    <td>
                        <asp:DropDownList ID="ddlCities" runat="server">
                        </asp:DropDownList>
                    </td>
                </tr>
            </table>
        </ItemTemplate>
        <SeparatorTemplate>
            <hr />
        </SeparatorTemplate>
    </asp:DataList>

    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            DataTable dt = new DataTable();
            dt.Columns.AddRange(new DataColumn[4] { new DataColumn("Name"), new DataColumn("Country"), new DataColumn("State"), new DataColumn("City") });
            dt.Rows.Add("John Mark");
            dt.Rows.Add("Ramesh Tandon");
            dt.Rows.Add("Mudassar Khan");
            dt.Rows.Add("James Anderson");
            DataList1.DataSource = dt;
            DataList1.DataBind();
        }
    }

    protected void OnItemDataBound(object sender, DataListItemEventArgs e)
    {
        if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem)
        {
            DropDownList ddlCountries = e.Item.FindControl("ddlCountries") as DropDownList;
            DropDownList ddlStates = e.Item.FindControl("ddlStates") as DropDownList;
            DropDownList ddlCities = e.Item.FindControl("ddlCities") as DropDownList;
            string query = "select CountryId, CountryName from Countries";
            BindDropDownList(ddlCountries, query, "CountryName", "CountryId", "Select Country");
            ddlStates.Enabled = false;
            ddlCities.Enabled = false;
            ddlStates.Items.Insert(0, new ListItem("Select State", "0"));
            ddlCities.Items.Insert(0, new ListItem("Select City", "0"));
        }
    }
    private void BindDropDownList(DropDownList ddl, string query, string text, string value, string defaultText)
    {
        string conString = ConfigurationManager.ConnectionStrings["ConString"].ConnectionString;
        SqlCommand cmd = new SqlCommand(query);
        using (SqlConnection con = new SqlConnection(conString))
        {
            using (SqlDataAdapter sda = new SqlDataAdapter())
            {
                cmd.Connection = con;
                con.Open();
                ddl.DataSource = cmd.ExecuteReader();
                ddl.DataTextField = text;
                ddl.DataValueField = value;
                ddl.DataBind();
                con.Close();
            }
        }
        ddl.Items.Insert(0, new ListItem(defaultText, "0"));
    }
    protected void Country_Changed(object sender, EventArgs e)
    {
        DropDownList ddlCountries = (sender as DropDownList);
        DataListItem item = (ddlCountries.NamingContainer as DataListItem);
        DropDownList ddlStates = item.FindControl("ddlStates") as DropDownList;
        DropDownList ddlCities = item.FindControl("ddlCities") as DropDownList;
        ddlStates.Enabled = false;
        ddlCities.Enabled = false;
        ddlStates.Items.Clear();
        ddlCities.Items.Clear();
        ddlStates.Items.Insert(0, new ListItem("Select State", "0"));
        ddlCities.Items.Insert(0, new ListItem("Select City", "0"));
        int countryId = int.Parse(ddlCountries.SelectedItem.Value);
        if (countryId > 0)
        {
            string query = string.Format("select StateId, StateName from States where CountryId = {0}", countryId);
            BindDropDownList(ddlStates, query, "StateName", "StateId", "Select State");
            ddlStates.Enabled = true;
        }
    }
    protected void State_Changed(object sender, EventArgs e)
    {
        DropDownList ddlStates = (sender as DropDownList);
        DataListItem item = (ddlStates.NamingContainer as DataListItem);
        DropDownList ddlCities = item.FindControl("ddlCities") as DropDownList;
        ddlCities.Enabled = false;
        ddlCities.Items.Clear();
        ddlCities.Items.Insert(0, new ListItem("Select City", "0"));
        int stateId = int.Parse(ddlStates.SelectedItem.Value);
        if (stateId > 0)
        {
            string query = string.Format("select CityId, CityName from Cities where StateId = {0}", stateId);
            BindDropDownList(ddlCities, query, "CityName", "CityId", "Select City");
            ddlCities.Enabled = true;
        }
    }