用combobox1的change事件就可以了 我这有一个例子,对你有没有启发
with query1 do
begin
close;
sql.clear;
sql.Add('select * from lei2.db');
sql.Add('where code2=r');
parambyname('pr').asstring:=cb1.Items.Strings[cb1.itemindex];
prepare;
open;
cb2.Items.Clear;
query1.first;
while not query1.eof do
begin