push notification helper library

http://windowsteamblog.com/windows_phone/b/wpdev/archive/2011/01/14/windows-push-notification-server-side-helper-library.aspx
http://create.msdn.com/en-us/education/catalog/article/pnhelp-wp7

main/Libs/PushRecipe_WP7_SL/Source/WindowsPhone.Recipes.Push.Client/Controls/ViewTransitions.cs

@@ -0,0 +1,43 @@
+using System;
+using System.Net;
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Documents;
+using System.Windows.Ink;
+using System.Windows.Input;
+using System.Windows.Media;
+using System.Windows.Media.Animation;
+using System.Windows.Shapes;
+using System.Collections.Generic;
+
+namespace WindowsPhone.Recipes.Push.Client.Controls
+{
+    public class ViewTransitions<T>
+    {
+        private class ViewTransition
+        {
+            public T To { get; set; }
+            public Action Action { get; set; }
+        }
+
+        public T _viewState;
+        private readonly Dictionary<T, ViewTransition> _transitions = new Dictionary<T, ViewTransition>();
+
+        public ViewTransitions(T initialState)
+        {
+            _viewState = initialState;
+        }
+
+        public void AddTransition(T from, T to, Action action)
+        {
+            _transitions[from] = new ViewTransition { To = to, Action = action };
+        }
+
+        public void Transition()
+        {
+            var transition = _transitions[_viewState];
+            _viewState = transition.To;
+            transition.Action();
+        }
+    }
+}