Enum Base filter on the forms in ax 2009

Formclass declaration
{
QueryBuildrange qbr;
}

DS int method
public void int()
{
    super();
    Qbr = this.query().datasourcetable(tablenum(III_Custtable)).addrange(fieldnum(III_Cutomer,Custtype));
}


PUblic void executeQuery()
{
     Qbr.value(custtype.valuestr());
    super();
}

on control level:-
selection change
public int selection change()
{
int ret;
ret = super();
III_custtable_ds.executeQuery()

}