Xamarin.Forms

Question

我正在尝试做的是在用户注册后，他们单击是，它将转到登录页面。否则用户单击 "Cancel" 它将进行注册，请帮助我..我是 xamarin

的新手

    void Handle_Clicked(object sender, System.EventArgs e)
    {
      string ConnectionString = "Server=10.0.2.2; Port=5432;User Id=postgres; Password=ncf123; Database=Accounting";
            try
            {
                NpgsqlConnection connection = new NpgsqlConnection(ConnectionString);
                connection.Open();
            }
            catch (Exception)
            {
                Console.WriteLine("adi na");

            }
            NpgsqlConnection connections = new NpgsqlConnection(ConnectionString);
            connections.Open();
            NpgsqlCommand command = connections.CreateCommand();
            command.CommandText = "INSERT INTO account(username, password, email, phonenumber) VALUES ( '" + EntryUsername.Text + "', '" + EntryPassword.Text + "','" + EntrEmail.Text + "','" + EntryPhoneNumber.Text + "')";
            try
            {
                NpgsqlDataReader reader = command.ExecuteReader();

                while (reader.Read())
                {
                    EntryUsername.Text = reader[0].ToString();
                    EntryPassword.Text = reader[1].ToString();
                    EntrEmail.Text = reader[2].ToString();
                    EntryPhoneNumber.Text = reader[3].ToString();

                }
            connections.Close();
            Device.BeginInvokeOnMainThread(async () =>
            {
                var result = await DisplayAlert("Congratulations", "User Registration Successfull", "Yes", "Cancel");
                if (result)
                {
                    await Navigation.PushAsync(new LoginPage());
                }
                else
                {
                    await Navigation.PushAsync(new registration());
                }

            });

        }
            catch (Exception ex)
            {
                Console.WriteLine(ex.ToString());
            }

更新这是我的 App.xaml.cs

public partial class App : Application
{
    public App()
    {
        InitializeComponent();

        MainPage = new registration();
    }

    protected override void OnStart()
    {
    }

    protected override void OnSleep()
    {
    }

    protected override void OnResume()
    {
    }
}

请大家帮帮我，我是 xamarin 和 postgresql 的新手

Answer 1

在您的 app.cs 中更改 MainPage = new MainPage();到 MainPage = new NavigationPage(new MainPage()); 其中 MainPage() 是您在启动应用程序时要打开的页面的名称

Xamarin.Forms - Android 上不支持全局 PushAsync，请使用 NavigationPage

Xamarin.Forms - PushAsync is not supported globally on Android, please use a NavigationPage

navigation

xamarin.android

xamarin