public override int GetHashCode()
 {
     return(MaChiTietPhieuTraNoKH.ToUpper().GetHashCode());
 }
 public override bool Equals(object obj)
 {
     return(MaChiTietPhieuTraNoKH.Equals(((eChiTietPhieuTraNoKhachHang)obj).MaChiTietPhieuTraNoKH));
 }