private void SearchButton_Clicked(object sender, EventArgs e)
 {
     FilterView.Hide();
     SearchButton.IsVisible = false;
     SearchBox.IsVisible    = true;
     SearchBox.Focus();
 }
        protected override bool BeforeBackButtonPressed()
        {
            if (FilterView.IsVisible)
            {
                FilterView.Hide();
                return(false);
            }

            if (SearchBox.IsVisible)
            {
                SearchBox.Unfocus();
                SearchBox.IsVisible    = false;
                SearchButton.IsVisible = true;
                return(false);
            }
            return(true);
        }