private void cbBoxCity_SelectedIndexChanged(object sender, EventArgs e)
        {
            var cityList = cbBoxCity.DataSource as List<Maticsoft.Model.City>;
            if (cityList == null)
            {
                return;
            }
            var cityInfo = cityList[cbBoxCity.SelectedIndex];

            var districtBll = new Maticsoft.BLL.District();
            var districtList = districtBll.GetModelList(String.Empty);
            cbbDistrict.DataSource = districtList.FindAll(x => x.CityID == cityInfo.CityID);
            cbbDistrict.DisplayMember = "DistrictName";
            cbbDistrict.ValueMember = "DistrictID";
        }
 public DistrictControl()
 {
     InitializeComponent();
     var provinces = new Maticsoft.BLL.Provinces();
     var provincesList = provinces.GetModelList(string.Empty);
     cbBoxProvinces.DataSource = provincesList;
     cbBoxProvinces.ValueMember = "ProvincesName";
     var provincesInfo = provincesList.FirstOrDefault();
     var cityBll = new Maticsoft.BLL.City();
     var cityList = cityBll.GetModelList(string.Empty);
     cityList = cityList.FindAll(x => provincesInfo != null && x.ProvincesID == provincesInfo.ProvincesID);
     cbBoxCity.DataSource = cityList;
     cbBoxCity.DisplayMember = "CityName";
     var cityInfo = cityList.FirstOrDefault();
     var districtBll = new Maticsoft.BLL.District();
     var districtList = districtBll.GetModelList(String.Empty);
     cbbDistrict.DataSource = districtList.FindAll(x => cityInfo != null && x.CityID == cityInfo.CityID);
     cbbDistrict.DisplayMember = "DistrictName";
 }