在VB.net中调用oracle数据库里的procedure的问题，返回值总是nothing？（

[allbrain]

procedure如下
PACKAGE crew_count
is
type outlist is ref cursor;

PROCEDURE get_crew_count(v_ac_reg in varchar2,v_sum_list out outlist);

END crew_count;

////////////////
PACKAGE BODY crew_count
is
PROCEDURE get_crew_count(v_ac_reg in varchar2,v_sum_list out outlist)
is
BEGIN
open v_sum_list
for

select tech_name,count(t3009.tech_no0)
from t3009,t3021
where t3009.tech_no0=t3021.tech_no and aircraft_type=v_ac_reg
group by tech_name;
END get_crew_count;

END crew_count;

vb.net里用oledbdataadapter导入了datatable，但是table里都是nothing,是不是outlist的游标在.net里返回类型不一致啊？
我又用function做了一下
package crew_count_test
is
type refcursor is ref cursor;
function get_crew_count_test(v_ac_reg in varchar2) RETURN refcursor;
end crew_count_test;
但是我不知道vb.net里怎么调function啊？
请指教~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~`