怎样将DBGrid里的内容保存为文本！！！

自己写文本文件。 var   MyTextFile:TextFile;AssignFile(MyTextFile,NameHdr/*文件名*/);
  ReWrite(MyTextFile);
  Try
    With adoqry_hdr do
    begin
      If not Eof then
      begin
      first;
        While not eof do
        begin
          WriteLn(MyTextFile,copy(Fields[0].Asstring+'                         ',1,25),
                           copy(Fields[1].Asstring+'           ',1,10),
                           copy(Fields[2].Asstring+'               ',1,15),
                           copy(Fields[3].Asstring+'           ',1,10),
                           copy(Fields[4].Asstring+'            ',1,11),
                           copy(Fields[5].Asstring+'            ',1,11),
                           copy(Fields[6].Asstring+'   ',1,3),
                           copy(Fields[7].Asstring+'   ',1,3),
                           copy(Fields[8].Asstring+'   ',1,3),
                           copy(Fields[9].Asstring+'                              ',1,30),
                           copy(Fields[10].Asstring+'                    ',1,20),
                           copy(Fields[11].Asstring+'                          ',1,25),
                           copy(Fields[12].Asstring+'                          ',1,25),
                           copy(Fields[13].Asstring+'                               ',1,30),
                           copy(Fields[14].Asstring+'           ',1,11),
                           copy(Fields[15].Asstring+'                                   ',1,35),
                           copy(Trim(Fields[16].Asstring)+'                                                                                                                                                                                                                                                               ',1,254),
                           copy(Trim(Fields[17].Asstring)+'                     ',1,20),
                           copy(Trim(Fields[18].Asstring)+'           ',1,10),
                           copy(Fields[19].Asstring+'             ',1,13),
                           copy(Fields[20].Asstring+'                                                                                                                                                                ',1,160),
                           copy(Fields[21].Asstring+' ',1,1),
                           copy(Fields[22].Asstring+'                              ',1,30),
                           copy(Fields[23].Asstring+'                                        ',1,40),
                           copy(Fields[24].Asstring+'                                                                                                                                                      ',1,150),
                           copy(Fields[25].Asstring+' ',1,1));
          next;
        end;
      end;
    end;  Finally
    CloseFile(MyTextFile);
  end;