(1) user interface paging
* It is easier to use,
* Lower performance because all data actually are loaded in the memory of the portal server.
* Support data source like Collection, DataSet, DataTable, DataView. Does not support DataReader. In my portal, the portal calls the web service to create a DataTable, which then is used to render a GridView. So this is a user interface paging. However, the web method can return only one page so as to simulate the paging behavior.
(2) data source paging
* Enable you to write custom logic to retrieve pages of database records.
* Can perform paging for store proc, Linq or a SQL query