Lazy loading images in Virtualized Listbox

Question

I\'m trying to lazy load thumbnail image for each item in a Listbox asynchronously.

Answer 1

Sounds like although your UI is virtualizing it isn't loading newer images quickly enough to keep up with your user's scrolling. Try setting VirtualizationMode to Recycling and set a longer CacheLength. Like so:

<ListBox
    VirtualizingPanel.IsContainerVirtualizable="True"
    VirtualizingPanel.IsVirtualizing="True"
    VirtualizingPanel.VirtualizationMode="Recycling"
    VirtualizingPanel.CacheLengthUnit="Page"
    VirtualizingPanel.CacheLength="2,2"
    etc.../>

Increasing CacheLength from "1,1" to "2,2" means two "pages" (or view-ports worth of items) will be loaded into memory before and after the page displayed to the user. Your app will consume that much more memory but users will be able to scroll further, faster, before running into images that aren't loaded.