/// <summary>
 ///		Obtiene la página seleccionada del árbol
 /// </summary>
 private TreePages.PageNodeViewModel GetPageFromTree(TreePages.TreePagesViewModel treePagesViewModel)
 {
     if (treePagesViewModel != null && treePagesViewModel.SelectedNode != null &&
         treePagesViewModel.SelectedNode is TreePages.PageNodeViewModel node)
     {
         return(node);
     }
     else
     {
         return(null);
     }
 }
 /// <summary>
 ///		Inicializa la vista del libro
 /// </summary>
 protected override void InitBookView()
 {
     TreePages = new TreePages.TreePagesViewModel(EBookContent);
     TreePages.PropertyChanged += (sender, evntArgs) =>
     {
         if (evntArgs.PropertyName.EqualsIgnoreCase(nameof(TreePages.SelectedNode)))
         {
             ShowPage(GetPageFromTree(sender as TreePages.TreePagesViewModel));
         }
     };
     TreePages.LoadNodes();
 }