suborms USE queries.
use the BUILDER to get the correct path to form/subform objects.
to use mulitiple controls, you must examine them all and build the where:
Code:
'----------------
sub btnFilter_click()
'----------------
dim sWhere as string
sWhere = "1=1"
if not IsNUll(cboST) then sWhere = sWhere & " and [State]='" & cboST & "'"
if not IsNUll(cboCity) then sWhere = sWhere & " and [city]='" & cboCity & "'"
if not IsNUll(cboZip) then sWhere = sWhere & " and [ZipCode]='" & cboZip & "'"
If sWhere = "1=1" Then
Me.FilterOn = False
Else
Me.Filter = sWhere
Me.FilterOn = True
End If
end sub