/// <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 async override void LoadState(Object navigationParameter, Dictionary<String, Object> pageState)
        {
            navParam = navigationParameter as postDate;
            pageTitle.Text = "Posts for " + navParam.month_name + " " + navParam.year;
            ViewCommentsButton.Visibility = Visibility.Collapsed;
            progressRing.Visibility = Visibility.Visible;
            Windows.UI.Xaml.Media.Animation.Storyboard sb =
                this.FindName("PopInStoryBoard") as Windows.UI.Xaml.Media.Animation.Storyboard;
            if (sb != null) sb.Begin();

            // TODO: Assign a bindable group to this.DefaultViewModel["Group"]
            // TODO: Assign a collection of bindable items to this.DefaultViewModel["Items"]
            FeedDataSource feedDataSource = (FeedDataSource)App.Current.Resources["feedDataSource"];
            if (feedDataSource != null)
            {
                await feedDataSource.GetFeedsAsync("date", navParam.year + navParam.month);
            }
            RootObject feedData = FeedDataSource.GetFeed();
            if (feedData != null)
            {
                this.DefaultViewModel["Feed"] = feedData;
                this.DefaultViewModel["Items"] = feedData.posts;
                if (feedData.posts.Count == 0)
                    itemTitle.Text = "There are no posts yet.";
            }

            if (pageState == null)
            {
                // When this is a new page, select the first item automatically unless logical page
                // navigation is being used (see the logical page navigation #region below.)
                if (!this.UsingLogicalPageNavigation() && this.itemsViewSource.View != null)
                {
                    this.itemsViewSource.View.MoveCurrentToFirst();
                }
                else
                {
                    //this.itemsViewSource.View.MoveCurrentToPosition(-1);
                }
            }
            else
            {
                // Restore the previously saved state associated with this page
                if (pageState.ContainsKey("SelectedItem") && this.itemsViewSource.View != null)
                {
                    // TODO: Invoke this.itemsViewSource.View.MoveCurrentTo() with the selected
                    //       item as specified by the value of pageState["SelectedItem"]
                    string itemTitle = (string)pageState["SelectedItem"];
                    Post selectedItem = FeedDataSource.GetItem(itemTitle);
                    this.itemsViewSource.View.MoveCurrentTo(selectedItem);
                }
            }
            if (feedData.posts.Count == 0)
                ViewCommentsButton.Visibility = Visibility.Collapsed;
            else ViewCommentsButton.Visibility = Visibility.Visible;
            progressRing.Visibility = Visibility.Collapsed;
        }
        /// <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 async override void LoadState(Object navigationParameter, Dictionary <String, Object> pageState)
        {
            navParam       = navigationParameter as postDate;
            pageTitle.Text = "Posts for " + navParam.month_name + " " + navParam.year;
            ViewCommentsButton.Visibility = Visibility.Collapsed;
            progressRing.Visibility       = Visibility.Visible;
            Windows.UI.Xaml.Media.Animation.Storyboard sb =
                this.FindName("PopInStoryBoard") as Windows.UI.Xaml.Media.Animation.Storyboard;
            if (sb != null)
            {
                sb.Begin();
            }

            // TODO: Assign a bindable group to this.DefaultViewModel["Group"]
            // TODO: Assign a collection of bindable items to this.DefaultViewModel["Items"]
            FeedDataSource feedDataSource = (FeedDataSource)App.Current.Resources["feedDataSource"];

            if (feedDataSource != null)
            {
                await feedDataSource.GetFeedsAsync("date", navParam.year + navParam.month);
            }
            RootObject feedData = FeedDataSource.GetFeed();

            if (feedData != null)
            {
                this.DefaultViewModel["Feed"]  = feedData;
                this.DefaultViewModel["Items"] = feedData.posts;
                if (feedData.posts.Count == 0)
                {
                    itemTitle.Text = "There are no posts yet.";
                }
            }

            if (pageState == null)
            {
                // When this is a new page, select the first item automatically unless logical page
                // navigation is being used (see the logical page navigation #region below.)
                if (!this.UsingLogicalPageNavigation() && this.itemsViewSource.View != null)
                {
                    this.itemsViewSource.View.MoveCurrentToFirst();
                }
                else
                {
                    //this.itemsViewSource.View.MoveCurrentToPosition(-1);
                }
            }
            else
            {
                // Restore the previously saved state associated with this page
                if (pageState.ContainsKey("SelectedItem") && this.itemsViewSource.View != null)
                {
                    // TODO: Invoke this.itemsViewSource.View.MoveCurrentTo() with the selected
                    //       item as specified by the value of pageState["SelectedItem"]
                    string itemTitle    = (string)pageState["SelectedItem"];
                    Post   selectedItem = FeedDataSource.GetItem(itemTitle);
                    this.itemsViewSource.View.MoveCurrentTo(selectedItem);
                }
            }
            if (feedData.posts.Count == 0)
            {
                ViewCommentsButton.Visibility = Visibility.Collapsed;
            }
            else
            {
                ViewCommentsButton.Visibility = Visibility.Visible;
            }
            progressRing.Visibility = Visibility.Collapsed;
        }