async void DownBlue_Tapped(object sender, System.EventArgs e)
 {
     await PageUp.TranslateTo(0, 0, 500, Easing.SinIn);
 }
 async void UpWhite_Tapped(object sender, System.EventArgs e)
 {
     await PageUp.TranslateTo(0, -Page.Height, 500, Easing.SinIn);
 }