DesktopHelper.UI.ConfigForm.comboBoxShi_SelectedIndexChanged C# (CSharp) Method

        private void comboBoxShi_SelectedIndexChanged(object sender, EventArgs e)
        {
            try
            {
                if (comboBoxShi.SelectedItem != null)
                {
                    ComboBoxItem shi = (ComboBoxItem)comboBoxShi.SelectedItem;
                    DataTable table_CityXian = _data.GetCityData(ConfigData.CityType.Xian, shi.Value);
                    if (table_CityXian != null && table_CityXian.Rows.Count > 0)
                    {
                        comboBoxXian.Items.Clear();
                        foreach (DataRow dr in table_CityXian.Rows)
                        {
                            comboBoxXian.Items.Add(new ComboBoxItem(dr["Name"].ToString(), dr["Code"].ToString()));
                        }
                    }
                }
                if (bool_IsStarting)
                {
                    for (int i = 0; i < comboBoxXian.Items.Count; i++)
                    {
                        ComboBoxItem item = comboBoxXian.Items[i] as ComboBoxItem;
                        if (item.Value.Equals(str_XIAN))
                        {
                            comboBoxXian.SelectedIndex = i;
                            break;
                        }
                    }
                }
                else
                {
                    BtnApply.Enabled = true;
                    comboBoxXian.SelectedIndex = 0;
                }
            }
            catch (Exception ex)
            {
                log.WriteLog(ex.ToString());
            }
        }