Refresh a Flex DataGrid

To force a Flex DataGrid to refresh its data (say, after you've updated it), you can call the invalidateDisplayList() method. This causes Flex to in turn execute the component's updateDisplayList() method. This came in handy while writing an image-upload app; after the image is uploaded, I needed the DataGrid's selectedItem to show the image it was associated with; in the overridden set data() method of the itemRenderer, there's code to do a load() of the image from the server.