当我单击xamarin中的按钮时，xamarin.forms发生未处理的异常

Question

The code of my project:

MainPage.xaml.cs:

using System; 
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms;

namespace App2
{
public partial class MainPage : ContentPage
{
    public MainPage()
    {
        InitializeComponent();
    }

    private async void Button_Clicked(object sender, EventArgs e)
    {
        await Navigation.PushAsync(new Page1());
    }
}
}

MainPage.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"
         xmlns:local="clr-namespace:App2"
         x:Class="App2.MainPage">

<Button Text="Welcome to Xamarin Forms!" 
       VerticalOptions="Center" 
       HorizontalOptions="Center" Clicked="Button_Clicked" />

 </ContentPage> 

In every project i create in xamarin when i click a button when in the android emulator i receive this message :

enter image description here

An unhandled exception occured.

And when i click the button in others projects it's give me the same message, please help me !

Answer 1

So i found that i have to change this line in app.xaml.cs from MainPage = new exercice2_stack_layout.MainPage(); to Mainpage = new NavigationPage (new MainPage()); to make the navigation.pushasync work perfectly .