public void AddVisit(int announ_id) { var visit_arr = (from a in db.visits where a.announ_id == announ_id select a); int visit_num = 0; int visit_id = 0; foreach (var item in visit_arr) { visit_num = item.visits_num.Value; visit_id = item.id; } if (visit_num == 0) { iproby.Data_Model.visit visit = new iproby.Data_Model.visit(); visit.announ_id = announ_id; visit.visits_num = visit_num + 1; db.visits.Add(visit); db.SaveChanges(); } else { var visit = db.visits.Find(visit_id); if (visit != null) { visit.visits_num = visit_num + 1; db.SaveChanges(); } } }