这不是问题吧?
你设置ComboBox2的enter事件:
if e.form.Controls("ComboBox1“).Value IsNot Nothing then
Dim dt AS DataTable = DataTables(e.form.Controls("ComboBox1“).Value)
dim s as String
for each dc as datacol in dt.datacols
s = s & "|" & dc.name
next
e.form.Controls("ComboBox2“).Combolist = s
end if