boolean checkData (CTableItem item, boolean redraw) {
	if (item.cached) return true;
	if ((getStyle () & SWT.VIRTUAL) != 0) {
		item.cached = true;
		Event event = new Event ();
		event.item = item;
		event.index = indexOf (item);
		notifyListeners (SWT.SetData, event);
		if (isDisposed () || item.isDisposed ()) return false;
		if (redraw) redrawItem (item.index, false);
	}
	return true;
}