//lay so luong sach nhap trong thang int GetSLNhap(int thang, int nam, string masach) { int soluongnhap = 0; SachBUS objSach = new SachBUS(); DataTable dtSLNhap = objSach.GetSoLuongNhap(thang, nam, masach); for (int j = 0; j < dtSLNhap.Rows.Count; j++) { soluongnhap += int.Parse(dtSLNhap.Rows[j]["soluong"].ToString()); } return(soluongnhap); }