Navigation among XAML Pages PCL

Hi everyone,

I am developing a cross platfom mobile app using Portable Class Libraries (PCL).

So far I have two XAML pages, lets call them pageone and pagetwo. In pageone I have a button and I want to use it to navigate to pagetwo. So I typed something like this:

pageone.xaml

<Button Text="blablabla" Clicked="Func1"...

pageone.xaml.cs

private void Func1(Object sender, EventArgs e)
{
this.Frame.Navigate(typeof(pagetwo), null);
}

but it doesn't work because this.Frame does not exist. Moreover I've found out that the NavigationService class is not available in PCL.

So what can I do?