public bool isContentExisted() { var obj = new { }; Dictionary <String, dynamic> param = new Dictionary <string, dynamic>(); param.Add(SachManager.Properties.TenSach, this.TenSach); param.Add(SachManager.Properties.TenTacGia, this.TenTacGia); param.Add(SachManager.Properties.LinhVucSach, this.LinhVucSach.MaSoLinhVuc); param.Add(SachManager.Properties.NXB, this.NXB.MaSoNXB); List <Sach> result = SachManager.findBy(param); if (result.Count > 0) { return(true); } return(false); }