访问嵌套报表powerbuilder

Datawindow ldwc_addpay
dw_1.getChild("dw_addpay",ldwc_addpay)
if ldwc_addpay.rowCount() <> 0 then

    for li_nestctr = 1 to ldwc_addpay.rowCount()

        ls_payamt = ldwc_addpay.getItemString(li_nestctr,"pay_amt")

        if not isnull(ls_payamt) and trim(ls_payamt) <> '' then ls_payamt = in_cryptoapi.of_Decrypt(ls_payment,"Key") 
        ldwc_addpay.setItem(li_nestctr, "pay_amt_dummy", double(ls_payamt)) 
        setnull(ls_payamt)

    next

end if

第二行和上一行不返回任何值(零),但第一行返回精确值。 **每一行都有工资扣除等。。