CP Vanity for Windows Phone 7

using System;
using System.Windows.Navigation;
using CPVanity.ViewModel;
using Microsoft.Phone.Controls;
using Microsoft.Phone.Shell;

namespace CPVanity
{
    public partial class MainPage : PhoneApplicationPage
    {
        private bool _newPageInstance;

        // Constructor
        public MainPage()
        {
            _newPageInstance = true;
            InitializeComponent();
        }

        protected bool IsResurrectedPage
        {
            get
            {
                return _newPageInstance && State.ContainsKey("PreservingPageState");
            }
        }

        protected override void OnNavigatedTo(NavigationEventArgs e)
        {
            base.OnNavigatedTo(e);

            if (IsResurrectedPage)
            {
                Dispatcher.BeginInvoke(() => State.RestoreState(Pivoter));
            }
        }

        protected override void OnNavigatedFrom(NavigationEventArgs e)
        {
            base.OnNavigatedFrom(e);

            // Set newPageInstance back to false. It will be set back to true if the constructor is called again.
            _newPageInstance = false;

            // Set a key in the State dictionary that will be checked for in OnNavigatedTo
            State["PreservingPageState"] = true;

            State.PreserveState(Pivoter);
        }

        private void ApplicationBarIconButton_Click(object sender, EventArgs e)
        {
            CPViewModel.TryExecuteCommand(DataContext, ((IApplicationBarIconButton)sender).Text);
        }
    }
}