void Completed(object sende, EventArgs e)
 {
     string m_huyen = App.nhomtd;
     QLThuebaoDomainContext dstb = new QLThuebaoDomainContext();
     EntityQuery<rp_tklydocat> Query = dstb.GetRp_tklydocatQuery();
     LoadOperation<rp_tklydocat> LoadOp = dstb.Load(Query.OrderBy(p => p.ma_dv), LoadOp_Complete, null);
 }