public void SignIn(string login, string password) { try { IServiceCallback callback = Callback; if (callback != null) { using (TestingSystemContext context = new TestingSystemContext()) { User user = context.Users.FirstOrDefault(u => u.Login.Equals(login)); if (user is null) { callback.ResultOfUserSignIn(null, "Пользователь с таким логином не найден!"); } else { if (user.Password.Equals(password)) { callback.ResultOfUserSignIn(user, ""); } else { callback.ResultOfUserSignIn(null, "Неверный пароль!"); } } } } } catch (Exception exception) { IServiceCallback callback = Callback; if (callback != null) { callback.ResultOfUserSignIn(null, exception.Message); } } }