var
  sl: TStringList;
  i,j: integer;
  s: string;
begin
  sl := TStringList.Create;
  try
    for i := 0 to DBGrid1.SelectedRows.Count -1 do begin
      GotoBookmark(pointer(DBGrid1.SelectedRows.Items[i]));
      s := '';
      for j := 0 to DBGrid1.DataSource.Dataset.FieldCount-1 do
        s := s   DBGrid1.DataSource.Dataset.Fields[j].AsString   #9; // 以 #9 這個字元隔開每個欄位的值
      sl.Add(s);
    end;
    sl.SaveToFile('C:\xxx');
  finally
    sl.Free;
  end;
end;