my $out = DBIx::Dump->new('format' => $format_pass, ...

##</code><code>##

if ($format_pass eq "csv") {$filename_pass.=csv;}else {$filename_pass.=xls;}
if (!$filename_pass) {$filename_pass=query.csv;}

##</code><code>##

<select type="option" name="format"><option>csv<option>xls</select>