private void detach_Lops(Lop entity)
 {
     this.SendPropertyChanging();
     entity.Khoa = null;
 }
 private void attach_Lops(Lop entity)
 {
     this.SendPropertyChanging();
     entity.Khoa = this;
 }
 partial void UpdateLop(Lop instance);
 partial void DeleteLop(Lop instance);
 partial void InsertLop(Lop instance);