WP7 Listbox how UI virtualization work

Question

I'm using ListBox which has VirtualizingStackPanel, which is said to support UI virtualizing by default.

However, when I set my listStudent (of type ObservableCollection, and have 5 Students in it) as ItemsSource for my Listbox. Then whenever user scroll to the end, I add another 5 Students to my listStudent (and of course UI is notified). But I see that memory consumed keep increased. There's no different from StackPanel in term of memory

How UI virtualization work? How to keep memory low when adding new item to listStudent?

Answer 1

virtualization means list do not construct the list items which you have not scroll to yet.

so you can put your test code to item's loaded function or used converter code. you can see whether virtualization works

for example

you can bind a converter to student's name prop and you can log it .then you know when the item create indeed

Answer 2

Ensure that you don't modified ListBox ItemsPanel that destroys UI virtualization

Answer 3

Sheldon_Xiao on has pointed out some references on MSDN that helpfully explain UI virtualizartion