如何在Xamarin窗体中的所有屏幕中显示TabbedPage？

using Xamarin.Forms;

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

            MainPage = new MainPage(); // 设置主页为TabbedPage
        }

        protected override void OnStart()
        {
            // Handle when your app starts
        }

        protected override void OnSleep()
        {
            // Handle when your app sleeps
        }

        protected override void OnResume()
        {
            // Handle when your app resumes
        }
    }

    public partial class MainPage : TabbedPage
    {
        public MainPage()
        {
            InitializeComponent();

            Children.Add(new HomePage()); // 添加子页面1
            Children.Add(new ProfilePage()); // 添加子页面2
            Children.Add(new SettingsPage()); // 添加子页面3
        }
    }

    public partial class HomePage : ContentPage
    {
        public HomePage()
        {
            InitializeComponent();

            // 添加首页内容
        }
    }

    public partial class ProfilePage : ContentPage
    {
        public ProfilePage()
        {
            InitializeComponent();

            // 添加个人资料页面内容
        }
    }

    public partial class SettingsPage : ContentPage
    {
        public SettingsPage()
        {
            InitializeComponent();

            // 添加设置页面内容
        }
    }
}