private async void SignInPassport() { //需要判断从哪里加载用户 UserLogin user = null; if (!_isExistingAccount) { UserName = UsernameTextBox.Text; UserPassword = UserpasswordTextBox.Text; user = new UserLogin(UserName, UserPassword); } else { UsernameTextBox.Text = UserLogin.Email; UserpasswordTextBox.Text = UserLogin.Password; user = UserLogin; } //暂时默认为成功 bool result = await Service.Login(user); if (result && UserAccountHelper.CheckCredential(user)) { if (!_isExistingAccount) { UserAccountHelper.AddAccount(user); UserAccountHelper.SaveAccountListAsync(); } Debug.WriteLine("the size of the list" + UserAccountHelper.UserAccounts.Count); Frame.Navigate(typeof(MainPage), null); } else { DialogCreator.CreateDialog("登陆失败", "登录失败请重新尝试"); } }