How to search an item in a load-on-demand WPF Treeview with MVVM pattern?

[Iamhe]

Mr Josh Smith implemented a search method in his wellknown article "Simplifying the WPF TreeView by Using the ViewModel Pattern". But this is implemented on a batch-loaded WPF treeview (his first example solution "Text Search"). What I want to know is: Is it possible to search an item in a load-on-demand WPF Treeview of MVVM pattern. In other words, is it possible to implement the searching way on Josh's second example solution "LoadOnDemand"? Thanks for your attention.

[迹象Kimizhou_blog]

With MVVM pattern it doesn't matter, should be searched