demo-xf-app-1a/MobileApp1/Views/HomePage.xaml.cs

using System;
using System.Threading.Tasks;
using Xamarin.Forms;
using Xamarin.Forms.Xaml;

namespace MobileApp1.Views
{
    [XamlCompilation(XamlCompilationOptions.Compile)]
    public partial class HomePage : ContentPage
    {
        public HomePage()
        {
            InitializeComponent();
        }

        private async void button1_Clicked(object sender, EventArgs e)
        {
            await Task.Run(() =>
            {
                ContentPageHelper.SetDetailPage(this, typeof(MyFoldersPage));
            });
        }

    }
}