The client side caching is static, this means that all items will be removed from the cache when the page is unloaded. Also all items that are shown into the grid are cached. So if you load initially the first page all items are cached, then when user navigates to the second page a request to the web service is perfumed and new data is loaded into the RadGrid. At this point the items for the second page are put into the cache. If the user returns to the first page the items will be got from the cache and there are not any requests to the web service. You can observe this behavior on our demo
by inspecting it with firebug or fiddler.
I hope this helps.
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