How to set up item renderers to have the created only if they are displayed on the viewport

I have data ItemRenderers with DataGroup, but I have many items, and it seems to me that DataGroup create all of them not only those few displayed on users screen, which takes time and resources.

H开发者_StackOverflow社区ow to setup ItemRenderer or DataGroup to save memory and performance?

You want virtualization of item renderers.

To configure a container to use virtual layout, set the useVirtualLayout property to true for the layout associated with the container. Only the DataGroup or SkinnableDataContainer with the VerticalLayout, HorizontalLayout, and TileLayout supports virtual layout.