/// <summary>
        /// Country dropdownlist SelectedIndexChanged event
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        protected void ddlCountry_SelectedIndexChanged(object sender, EventArgs e)
        {
            // Remove region dropdownlist items
            ddlRegion.Items.Clear();
            string strCountry = string.Empty;

            strCountry = ddlCountry.SelectedValue;
            List <string> list = null;

            // Bind Region dropdownlist based on country value
            if (ddlCountry.SelectedIndex != 0)
            {
                list = RetrieveDataFromXml.GetRegionByCountry(strCountry);
                if (list != null && list.Count != 0)
                {
                    ddlRegion.Enabled = true;
                }

                ddlRegion.DataSource = list;
                ddlRegion.DataBind();
            }
            else
            {
                ddlRegion.Enabled = false;
            }

            ddlRegion.Items.Insert(0, new ListItem("Select Region", "-1"));

            // Clear city dropdownlist
            ddlCity.Enabled = false;
            ddlCity.Items.Clear();
            ddlCity.Items.Insert(0, new ListItem("Select City", "-1"));

            // Initialize city dropdownlist selected index
            hdfDdlCitySelectIndex.Value = "0";
        }
        /// <summary>
        /// Get region basing on country value
        /// </summary>
        /// <param name="strValue">The country value</param>
        public void RetrieveRegionByCountry(string strValue)
        {
            List <string> list = RetrieveDataFromXml.GetRegionByCountry(strValue);

            WriteData(list);
        }