public void HoaDonDichVu_Load(int _HoaDonDichVuID)
        {
            LoadingPanel.IsBusy = true;

            DichVuClient = new DichVuSVCClient();
            DichVuClient.DichVu_GetItemsCompleted += new EventHandler<DichVu_GetItemsCompletedEventArgs>(DichVuClient_DichVu_GetItemsCompleted);
            DichVuClient.DichVu_GetItemsAsync();
            cbxDichVu.SelectedIndex = 0;

            if (_HoaDonDichVuID != 0)
            {
                HoaDonDichVuID = _HoaDonDichVuID;
                HoaDonDichVuClient = new HoaDonDichVuSVCClient();
                HoaDonDichVuClient.HoaDonDichVu_GetItemCompleted += new EventHandler<HoaDonDichVu_GetItemCompletedEventArgs>(HoaDonDichVuClient_HoaDonDichVu_GetItemCompleted);
                HoaDonDichVuClient.HoaDonDichVu_GetItemAsync(HoaDonDichVuID);
            }
        }