[XF] NavigationPage - 強制回應

需要使用者強迫回應選擇時，可以使用 NavigationPage - Model

app.xaml.cs

using Xamarin.Forms;

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

            MainPage = new NavigationPage(new Page1());
        }

        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
        }
    }
}

Page1.xaml

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="NaviModel.Page1"
             Title="第一頁">
    <ContentPage.Content>
        <StackLayout>
            <Button x:Name="P1GoNext" Text ="到第二頁"  Clicked="P1GoNext_Clicked"></Button>
        </StackLayout>
    </ContentPage.Content>
</ContentPage>

Page1.xaml.cs

namespace NaviModel
{
 [XamlCompilation(XamlCompilationOptions.Compile)]
 public partial class Page1 : ContentPage
 {
  public Page1 ()
  {
   InitializeComponent ();
  }

        private void P1GoNext_Clicked(object sender, EventArgs e)
        {
            this.Navigation.PushModalAsync(new Page2());
        }
    }
}

Page2.xaml

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="NaviModel.Page2"
             Title="第二頁">
    <ContentPage.Content>
        <StackLayout>
            <Button x:Name="P2GoPre" Text ="到第一頁" Clicked="P2GoPre_Clicked"> </Button>
        </StackLayout>
    </ContentPage.Content>
</ContentPage>

Page2.xaml.cs

using Xamarin.Forms;
using Xamarin.Forms.Xaml;

namespace NaviModel
{
 [XamlCompilation(XamlCompilationOptions.Compile)]
 public partial class Page2 : ContentPage
 {
  public Page2 ()
  {
   InitializeComponent ();
  }

        private void P2GoPre_Clicked(object sender, EventArgs e)
        {
            this.Navigation.PopModalAsync();
        }
    }
}

從下圖可以觀察到 Model Page 是不會有巡覽列，也就是不會有 Back 鍵生成



最後，Model Page 內是無法混用 Modelless Page 的喔

參考資料
• Xamarin.Forms-帶領你用最有效率的方式開發APP
• 在 Xamarin.Forms 中使用NavigationPage 的多頁面巡覽與切換…
• 強制回應頁面