private async Task NavigatePage()
        {
         Device.BeginInvokeOnMainThread(async () => {
    await _navigationService.NavigateAsync("MainPage?selectedTab=Tab2Page/TargetPage");
        });
}//This returns a blank page

private async Task TryNavigating()
    {
          Device.BeginInvokeOnMainThread(async () =>
                {
            await _navigationService.NavigateAsync("/NavigationPage/MainPage?selectedTab=Tab2Page/TargetPage");
                });
    }