public static int AddOrUpdateBiTich(BiTich biTich)
        {
            int _idGiaoDan = 0;

            using (QLGIAOXU db = new QLGIAOXU())
            {
                BiTich tmp = db.BiTich.Where(u => u.IDGiaoDan == biTich.IDGiaoDan).FirstOrDefault();
                if (tmp != null)
                {
                    tmp.NgayRLLD     = biTich.NgayRLLD;
                    tmp.NgayRuaToi   = biTich.NgayRuaToi;
                    tmp.NgayThemSuc  = biTich.NgayThemSuc;
                    tmp.NguoiDoDauRT = biTich.NguoiDoDauRT;
                    tmp.NguoiDoDauTS = biTich.NguoiDoDauTS;
                    tmp.NguoiRuaToi  = biTich.NguoiRuaToi;
                    tmp.NguoiThemSuc = biTich.NguoiThemSuc;
                    tmp.SoRLLD       = biTich.SoRLLD;
                    tmp.SoRuaToi     = biTich.SoRuaToi;
                    tmp.SoThemSuc    = biTich.SoThemSuc;
                    tmp.NoiRLLD      = biTich.NoiRLLD;
                    tmp.NoiRuaToi    = biTich.NoiRuaToi;
                    tmp.NoiThemSuc   = biTich.NoiThemSuc;
                }
                else
                {
                    db.BiTich.Add(biTich);
                }
                int x = db.SaveChanges();
                if (x > 0)
                {
                    _idGiaoDan = x;
                }
            }
            return(_idGiaoDan);
        }
        public static BiTichEntity GetBiTich(int?idGiaoDan)
        {
            BiTich       _tmp    = null;
            BiTichEntity _bitich = new BiTichEntity();

            using (QLGIAOXU db = new QLGIAOXU())
            {
                if (idGiaoDan != 0)
                {
                    _tmp = (from u in db.BiTich where (u.IDGiaoDan == idGiaoDan) select u).FirstOrDefault();
                }
                if (_tmp != null)
                {
                    _bitich.NgayRLLD     = _tmp.NgayRLLD;
                    _bitich.NgayRuaToi   = _tmp.NgayRuaToi;
                    _bitich.NgayThemSuc  = _tmp.NgayThemSuc;
                    _bitich.NguoiDoDauRT = _tmp.NguoiDoDauRT;
                    _bitich.NguoiDoDauTS = _tmp.NguoiDoDauTS;
                    _bitich.NguoiRuaToi  = _tmp.NguoiRuaToi;
                    _bitich.NguoiThemSuc = _tmp.NguoiThemSuc;
                    _bitich.NoiRLLD      = _tmp.NoiRLLD;
                    _bitich.NoiRuaToi    = _tmp.NoiRuaToi;
                    _bitich.NoiThemSuc   = _tmp.NoiThemSuc;
                    _bitich.SoRLLD       = _tmp.SoRLLD;
                    _bitich.SoRuaToi     = _tmp.SoRuaToi;
                    _bitich.SoThemSuc    = _tmp.SoThemSuc;
                }
            }
            return(_bitich);
        }