/// <summary>
/// Populates the page with content passed during navigation. Any saved state is also
/// provided when recreating a page from a prior session.
/// </summary>
/// <param name="navigationParameter">The parameter value passed to
/// <see cref="Frame.Navigate(Type, Object)"/> when this page was initially requested.
/// </param>
/// <param name="pageState">A dictionary of state preserved by this page during an earlier
/// session. This will be null the first time a page is visited.</param>
protected override void LoadState(Object navigationParameter, Dictionary <String, Object> pageState)
{
// TODO: Assign a bindable group to this.DefaultViewModel["Group"]
// TODO: Assign a collection of bindable items to this.DefaultViewModel["Items"]
var cart = SampleDataSource.GetCart();
this.DefaultViewModel["Group"] = cart;
this.DefaultViewModel["Items"] = cart.Items;
}