private void listConversations_SelectionChanged(object sender, SelectionChangedEventArgs e) { var item = (ListBox)sender; friendList = (ConversationsModel)item.SelectedItem; if (friendList != null) { if (MessageFrame.CanGoBack) { MessageFrame.GoBack(); MessageFrame.Navigate(typeof(HistoryPage), friendList, new DrillInNavigationTransitionInfo()); } else { MessageFrame.Navigate(typeof(HistoryPage), friendList, new DrillInNavigationTransitionInfo()); } } }