Canvas does not have support for UI virtualization, in Silverlight or WPF. VirtualizingStackPanel is the one panel that does.

Thanks,
Bea

is it possible to use virtualization in Silverlight 3 on Canvas?

Thanks in advance!
Michael

Sorry for the super late reply, but I was overseas.

Unfortunately I still haven’t gotten the keyboard navigation working properly. I spent a few hours after my posting trying, but a lot of things in the ComboBox and Selector classes are marked as internal to the System.Windows assembly, making it very difficult to implement.
The keyboard navigation works fine when the drop down of my VirtualizingComboBox is closed, but doesn’t work properly when the drop down is open. Due to time constraints I left the VirtualizingComboBox as is.

I am interested in Thomas’ solution further down below (thanks Thomas) and hope that he posts some code. I might look at the AutoCompleteBox code myself in Reflector when I revisit this problem at a later stage.

Thanks Bea.

Another workaround for the ComboBox issue is to use a AutoCompleteBox with a template so it looks like a combobox.
This should work since the AutoCompleteBox internally uses a ListBox.

I will post some code later.

Thomas

I had the problem that virtualisation helped me but scrolling went slow because my listbox’s items are too big to load fast enough to scroll fluently. Recycling worked but just for a few seconds until garbadge collector came. So I did a little trick: Each time an item loads I add a reference to the control in which the listbox exist which causes that garbadge collector has to go home with empty hands and scrolling spikes just for the first time.

You would need to re-implement significant portions of the virtualization code, though, such as VirtualizingStackPanel and ItemContainerGenerator and potentially more. It would be possible, but not straightforward, so it really depends how much time and motivation you have to solve this problem. If you do decide to take on the challenge, please tell me about it and I’ll advertise it on my blog.

Bea

Now the question i ask is this, if we didn’t care about setting the size of the thumb and actually wanted to hide the scrollbar and only expose a touch like way of navigating the list (like the iPhone scroll lists). Could we somehow tweak the virtualized logic to work for pixel based movement and just ignore setting the thumb heights?

Basically is the only reason for using item based scrolling for virtualized lists because of the thumb and setting it to the correct height?