EntityFramework.dll中发生类型为'System.Data.Entity.Infrastructure.DbUpdateException'的异常

Question

I'm trying to update my database. The exception "An exception of type 'System.Data.Entity.Infrastructure.DbUpdateException' occurred in EntityFramework.dll but was not handled in user code" occurs at db.SaveChanges().

I get the last id from the table "Ekipa", and set the new id as "value + 1". I set all the properties, which I get from the form. Then I set the currentUser's foreignKey, which is the same as the new entry id. I set the state as modified, but I still get the error. Does anyone see any problems with it? It used to work fine, but I recently changed the foreignKey from being and "int", to "int?" (so it's now nullable). Is that the problem, or am I missing something here?

  int value = int.Parse(db1.Ekipa
                                .OrderByDescending(p => p.id)
                                .Select(r => r.id)
                                .First().ToString());
                    int geslo = 0;
                    int NovaId = value;
                    Int32.TryParse(EkipaGeslo, out geslo);
                    Ekipa nova = new Ekipa();
                    nova.id = value + 1;
                    nova.Ime = EkipaIme;
                    nova.Geslo = geslo;
                    nova.LeaderID = currentUser.AccountID;
                    currentUser.EkipaId = nova.id;
                    db.Entry(currentUser).State = System.Data.Entity.EntityState.Modified;
                    db.SaveChanges();
                    db1.Ekipa.Add(nova);
                    db1.SaveChanges();

Answer 1

Apparently my "Ekipa" table was somehow deleted, and nothing was refreshing. Fixed it by recreating it