/// <summary>
        /// Region dropdownlist SelectedIndexChanged event
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        protected void ddlRegion_SelectedIndexChanged(object sender, EventArgs e)
        {
            // Bind city dropdownlist based on region value
            string strRegion = string.Empty;

            strRegion = ddlRegion.SelectedValue;
            List <string> list = null;

            list = RetrieveDataFromXml.GetCityByRegion(strRegion);
            ddlCity.Items.Clear();
            ddlCity.DataSource = list;
            ddlCity.DataBind();
            ddlCity.Items.Insert(0, new ListItem("Select City", "-1"));

            // Initialize city dropdownlist selected index
            hdfDdlCitySelectIndex.Value = "0";

            // Enable city dropdownlist when it has items
            if (list.Count > 0)
            {
                ddlCity.Enabled = true;
            }
            else
            {
                ddlCity.Enabled = false;
            }
        }
        /// <summary>
        /// Get city basing on region value
        /// </summary>
        /// <param name="strValue">The region value</param>
        public void RetrieveCityByRegion(string strValue)
        {
            List <string> list = RetrieveDataFromXml.GetCityByRegion(strValue);

            WriteData(list);
        }