xamwpf1

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using Xamarin.Forms;
using Xamarin.Forms.Platform.WPF;

namespace N2M_enwis.WPF
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : FormsApplicationPage
    {

        public class mrenderer : IVisualElementRenderer
        {
            public VisualElement Element => throw new NotImplementedException();

            public event EventHandler<VisualElementChangedEventArgs> ElementChanged;

            public void Dispose()
            {
                throw new NotImplementedException();
            }

            public SizeRequest GetDesiredSize(double widthConstraint, double heightConstraint)
            {
                throw new NotImplementedException();
            }

            System.Windows.Controls.Grid ng = null;
            public FrameworkElement GetNativeElement()
            {
                if (ng == null)
                    ng = new System.Windows.Controls.Grid();
                ng.Width = ng.Height = 200;
                ng.Background = new SolidColorBrush(System.Windows.Media.Color.FromRgb(0, 0, 55));
                return ng;
            }

            public void SetElement(VisualElement element)
            {
                throw new NotImplementedException();
            }
        }
        public MainWindow()
        {
            StackLayout sl = new StackLayout();

            InitializeComponent();
            Forms.Init();
            var app = new N2M_enwis.App();
            LoadApplication(app);

            app.MainPage = new ContentPage();
            ((ContentPage)app.MainPage).Content = sl;
            app.MainPage.BackgroundColor = Xamarin.Forms.Color.Green;
            sl.WidthRequest = sl.HeightRequest = 1000;
            sl.BackgroundColor = Xamarin.Forms.Color.Yellow;

            var rnd = Xamarin.Forms.Platform.WPF.Platform.GetOrCreateRenderer(sl);
            Xamarin.Forms.Platform.WPF.FormsPanel ffelem = (Xamarin.Forms.Platform.WPF.FormsPanel)rnd.GetNativeElement();

            var newrend = new mrenderer();
            Xamarin.Forms.Platform.WPF.Platform.SetRenderer(sl, newrend);

            ffelem.Background = new SolidColorBrush(System.Windows.Media.Color.FromRgb(150,150,255));
            ffelem.Opacity = 0.5;

            var grid = new System.Windows.Controls.Grid();
            grid.Background = new SolidColorBrush(System.Windows.Media.Color.FromRgb(0, 0, 55));
            grid.Width = grid.Height = 200;

            ffelem.Children.Add(grid);
            grid.BringIntoView();
            ffelem.Children.Add(new System.Windows.Controls.Button());
            ffelem.Children.Add(new System.Windows.Controls.Button());
            ffelem.Children.Add(new System.Windows.Controls.Button());
            ffelem.Children.Add(new System.Windows.Controls.Button());
            ffelem.Children.Add(new System.Windows.Controls.Button());
            grid.Children.Add(new System.Windows.Controls.Button());
            grid.Children.Add(new System.Windows.Controls.Button());

            /*
            var btn = new System.Windows.Controls.Label();
            btn.Background = new SolidColorBrush(System.Windows.Media.Color.FromRgb(10, 10, 10));
            btn.MinWidth = 300;
            btn.MinHeight = 300;
            btn.Visibility = Visibility.Visible;
            btn.Content = "ztes";
            ffelem.Children.Add(btn);
            ffelem.UpdateLayout();*/
        }
    }
}