public void checkStudent() { int sid = Convert.ToInt32(txtStudentID.Text); var student = lbManageEntity.tbl_student.Where(x => x.StudentId == sid).FirstOrDefault(); if (student != null) { lbManageEntity.AddTotbl_StudentLogin(studentLib); lbManageEntity.SaveChanges(); CleanAll(); } else { lblMessafe.Text = "Incorrect Student ID Pleace cofirm your id"; } }