Using 7-Zip from Delphi?

uses
   JclCompression;

procedure TfrmSevenZipTest.Button1Click(Sender: TObject);
const
   FILENAME = 'F:temptest.zip';
var
   archiveclass: TJclDecompressArchiveClass;
   archive: TJclDecompressArchive;
   item: TJclCompressionItem;
   s: String;
   i: Integer;
begin
   archiveclass := GetArchiveFormats.FindDecompressFormat(FILENAME);

   if not Assigned(archiveclass) then
      raise Exception.Create('Could not determine the Format of ' + FILENAME);

   archive := archiveclass.Create(FILENAME);
   try
      if not (archive is TJclSevenZipDecompressArchive) then
         raise Exception.Create('This format is not handled by 7z.dll');

      archive.ListFiles;

      s := Format('test.zip Item Count: %d'#13#10#13#10, [archive.ItemCount]);

      for i := 0 to archive.ItemCount - 1 do
      begin
         item := archive.Items[i];
         case item.Kind of
            ikFile:
               s := s + IntToStr(i+1) + ': ' + item.PackedName + #13#10;
            ikDirectory:
               s := s + IntToStr(i+1) + ': ' + item.PackedName + ''#13#10;//'
         end;
      end;

      if archive.ItemCount > 0 then
      begin
//         archive.Items[0].Selected := true;
//         archive.ExtractSelected('F:temptest');

         archive.ExtractAll('F:temptest');
      end;

      ShowMessage(s);
   finally
      archive.Free;
   end;
end;