public override void Handle(ChangeMarkCommand command) { Mark mark = _dbContext.Marks.Find(command.Id); if (mark == null) { _result = new InvalidResult() .WithError("No mark of this id has been found."); } mark.ChangeName(command.Name); mark.ChangeDescription(command.Description); _dbContext.Marks.Update(mark); _dbContext.SaveChanges(); _result = new SuccessResult(); }