void HoaDonClient_HoaDon_GetItemCompleted(object sender, HoaDon_GetItemCompletedEventArgs e)
 {
     HoaDonInfo HoaDon = e.Result;
     PhongClient = new PhongSVCClient();
     PhongClient.TinhTrang_Phong_EditCompleted += new EventHandler<System.ComponentModel.AsyncCompletedEventArgs>(PhongClient_TinhTrang_Phong_EditCompleted);
     PhongClient.TinhTrang_Phong_EditAsync(HoaDonID,(int)cbxPhong.SelectedValue);
 }