protected void bt_Delete_Click(object sender, EventArgs e)
    {
        if ((int)ViewState["PriceID"] > 0)
        {
            PDT_StandardPriceBLL bll = new PDT_StandardPriceBLL((int)ViewState["PriceID"]);

            foreach (ListItem item in cbl_ApplyCity.Items)
            {
                if (item.Selected)
                {
                    bll.DeleteApplyCity(int.Parse(item.Value));
                }
            }

            BindCheckBoxList();
        }
    }