Using DataPager without retrieving all rows on each request

int total;
List<Client> clientList =
    clientData.GetClients(criteria, pageNum, pageSize, out total);
uxClientList.DataSource = clientList;
uxClientList.DataBind();

List<Client> clientList = clientData.GetClients(criteria);
uxClientList.DataSource = clientList;
uxClientList.DataBind();