Enable Paging in Ax 2009

static void ABTest(Args _args)
{
 Query query = new Query(Querystr('ABTest'));
 salestable salestable;

//query query = new Query();
QueryBuildDataSource qbds;
QueryRun qr;
tableid tableid;



qbds = query.dataSourceTable(tablenum(salestable));
//Order by item id
qbds.addOrderByField(fieldnum(salestable,salesid));
//Instantiate a Queryrun class
qr = new QueryRun(Query);
//Enable Ordering
qr.literals(true);
// Enable position paging for the queryrun object
qr.enablePositionPaging(true);
//Add a range by providing the parameters as starting record number and number of records
qr.addPageRange(10,20);
while(qr.next())
{
salestable = qr.get(tablenum(salestable));
info(salestable.SalesId);
}

}