listview加载图片，先加载当前lsitview可见域图片的项，当移动滚动条又继续加载，有木有这方面的代码。（主要是listview木有滚动条事件）查了下网上，找不到。求助！
------解决思路----------------------
http://www.codeproject.com/Articles/7554/Getting-Scroll-Events-for-a-Listbox
http://stackoverflow.com/questions/9909462/how-to-make-scroll-event-for-listview