登录成功时的 Xamarin 窗体导航

Question

我开发了一个WebApi项目，它使用MS Identitity并向Html/Jquery客户端提供数据。我第一次尝试 Xamarin 表单并遵循教程。我已经到了可以成功发布登录条件并接收持有者令牌的阶段，并使用 Xam Plugins.Settings 存储它。我可以在将来的请求中很好地使用此令牌并很好地接收数据。 我正在努力实现导航，因此当用户单击登录按钮并获得令牌时，该应用程序将"重定向"到视图 GSMUnitsPage((。目前，用户单击该按钮并登录正常，但它位于同一登录屏幕上。我通过创建一个可以正常工作的 GSMUnitsPage 按钮来证明一切正常。

登录视图模型：

class LoginViewModel
{
public string Email { get; set; }
public string Password { get; set; }
public ICommand LoginCommand
{
get
{
return new Command(async () =>
{
ApiServices apiServices = new ApiServices();
var accesstoken = await apiServices.LoginUserAsync(Email, Password);
Settings.AccessToken = accesstoken;
});
}
}
public LoginViewModel()
{
Email = Settings.Username;
Password = Settings.Password;
}
}

登录接口：

public async Task<string> LoginUserAsync(string email, string password)
{
var client = new HttpClient();
var keyValues = new List<KeyValuePair<string, string>>
{
new KeyValuePair<string, string>("username", email),
new KeyValuePair<string, string>("password", password),
new KeyValuePair<string, string>("grant_type", "password")
};
var request = new HttpRequestMessage(
HttpMethod.Post, "linktotoken");
request.Content = new FormUrlEncodedContent(keyValues);
var reponse = await client.SendAsync(request);
var jwt = await reponse.Content.ReadAsStringAsync();
JObject jwtDyanmic = JsonConvert.DeserializeObject<dynamic>(jwt);
var accessToken = jwtDyanmic.Value<string>("access_token");
var accessTokenExpiration = jwtDyanmic.Value<DateTime>(".expires");
Settings.AccessTokenExpiration = accessTokenExpiration;
Debug.WriteLine(jwt);
return accessToken;
}

LoginPage.xaml：

<ContentPage.BindingContext>
<vm:LoginViewModel/>
</ContentPage.BindingContext>

<StackLayout VerticalOptions="Center">
<Entry Text="{Binding Email}" />
<Entry Text="{Binding Password}" />
<Button Command="{Binding LoginCommand}" Text="Login/Signin" />
</StackLayout>

应用xaml.cs

public App ()
{
InitializeComponent();
SetMainPage();
}
private void SetMainPage()
{
if (!string.IsNullOrEmpty(Settings.AccessToken))
{
if (DateTime.UtcNow.AddHours(1) > Settings.AccessTokenExpiration)
{
var vm = new LoginViewModel();
vm.LoginCommand.Execute(null);
}
MainPage = new NavigationPage(new GSMUnitsPage());
}
else if(!string.IsNullOrEmpty(Settings.Username) && !string.IsNullOrEmpty(Settings.Password))
{
MainPage = new NavigationPage(new LoginPage());
}
else
{
MainPage = new NavigationPage(new RegisterPage());
}
}

Answer 1

在 LoginCommand 上设置 Settings.AccessToken 后尝试调用 App.SetMainPage(( 方法。 (您可能希望公开设置主页(

public ICommand LoginCommand
{
get
{
return new Command(async () =>
{
ApiServices apiServices = new ApiServices();
var accesstoken = await apiServices.LoginUserAsync(Email, Password);
Settings.AccessToken = accesstoken;
App.SetMainPage();
});
}
}