How do I work like Contacts?

The contacts of windows mobile 5.0, it can:

1)view by name and view by company in a single Listbox .

When view by company, the listbox can work like Treeview. As soon as you tap one of company , it can expand and show the correlative contact people, then, tap it again, it can collapse immediately. All of them are carried out in the one listbox.

How can I do it I try it out, but I can not accomplish it.

I selected listboxEx of opennetCF, first, I overried listitem, and gave a bool as flag whether it was tapped, if the listitem was true, the correlative contact people were added to the listboxEx when tapped, and if it was false, the correlative contact people were removed when tapped.

But I think it is thickheaded idea, who can help me

2)Adjust height of item.

When the item has three lines or more , the item of listbox can adjust itemheight.

Listbox in .net compact framwork can only specify itemheight one time, actually, it cannot change, in other words, all the items of listbox has only the same height.

How can I work like Contacts of windows mobile 5.0