Alistar ViewModel-View Page transition system

Navigator.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.Serialization;
using System.Windows.Controls;
using Microsoft.Phone.Controls;
using Microsoft.Phone.Shell;

namespace Linearstar.Alistar.ViewModels
{
	public static class Navigator
	{
		const string StateKey = "Navigator";
		static readonly Random r = new Random();
		static Stack<object> stack = new Stack<object>();

		public static void Load()
		{
			if (PhoneApplicationService.Current.State.ContainsKey(StateKey))
			{
				var state = PhoneApplicationService.Current.State[StateKey];
				var dcsl = new Dictionary<Type, DataContractSerializer>();

				stack = new Stack<object>(((byte[][])state).Select(_ =>
				{
					using (var ms = new MemoryStream(_))
					using (var br = new BinaryReader(ms))
					{
						var type = Type.GetType(br.ReadString());
						var dcs = dcsl.ContainsKey(type) ? dcsl[type] : dcsl[type] = new DataContractSerializer(type);

						return dcs.ReadObject(ms);
					}
				}));
				PhoneApplicationService.Current.State.Remove(StateKey);
			}
		}

		public static void Save()
		{
			var dcsl = new Dictionary<Type, DataContractSerializer>();

			stack.Push(((PhoneApplicationPage)((Frame)App.Current.RootVisual).Content).DataContext);

			PhoneApplicationService.Current.State[StateKey] = stack.Select(_ =>
			{
				var type = _.GetType();
				var dcs = dcsl.ContainsKey(type) ? dcsl[type] : dcsl[type] = new DataContractSerializer(type);

				using (var ms = new MemoryStream())
				using (var bw = new BinaryWriter(ms))
				{
					bw.Write(type.AssemblyQualifiedName);
					dcs.WriteObject(ms, _);

					return ms.ToArray();
				}
			}).ToArray();
		}

		public static T GetFromStore<T>(PhoneApplicationPage page)
		{
			return (T)(page.DataContext ?? stack.Pop());
		}

		public static void Navigate<T>(T viewModel)
		{
			GC.Collect();

			var frame = (Frame)App.Current.RootVisual;
			var type = typeof(T).FullName;
			var url = "/Alistar;component/" + type.Replace("Linearstar.Alistar.ViewModels", "Views").Replace(".", "/").Replace("ViewModel", "Page.xaml") + "?r=" + r.Next();

			stack.Push(viewModel);
			frame.Navigate(new Uri(url, UriKind.Relative));
		}
	}
}