void laythongtin()
 {
     QLThuebaoDomainContext dbs = new QLThuebaoDomainContext();
     EntityQuery<ma_diaban> Query = dbs.GetMa_diabanQuery();
     LoadOperation<ma_diaban> Load = dbs.Load(Query.Where(p => p.ma_huyen == App.ma_huyen && p.kt == App.kythuat), lo => { gridControl1.ItemsSource = lo.Entities; }, null);             
 }