packed record用意在於你自訂的Record它的Size不會因為程式最佳化的影響而被調整成4的倍數.    type
  TRec = packed record
          I: Word;
    A: Integer;
    B: Byte;
    C: Word;
    D: Char;
  end;    implementation    procedure TForm1.Button2Click(Sender: TObject);
var
  I, ByteRead, Count: Integer;
  R: TRec;
  P: array of TRec;
  F: TFileStream;
begin
  F := TFileStream.Create('C:\TEST.DAT', fmCreate);
  try
    for I := 0 to 99 do
    begin
      R.I := I;
      R.A := Random(MaxInt);
      R.B := Random(MaxByte);
      R.C := Random(MaxWord);
      R.D := Char(Random(MaxByte));
      F.Write(R, SizeOf(R));
    end;
  finally
    F.Free;
  end;      if FileExists('C:\TEST.DAT') then
  begin
    F := TFileStream.Create('C:\TEST.DAT', fmOpenRead);
    try
      SetLength(P, 100); //配置 100 筆資料所需記憶體
      try
        ByteRead := SizeOf(TRec) * Length(P);
        ByteRead := F.Read(Pointer(P)^, ByteRead);
        Count := ByteRead div SizeOf(TRec);
        ListBox1.Clear;
        for I := 0 to Count-1 do
           ListBox1.Items.Add(IntToStr(P[I].I));
      finally
        P := nil;
      end;
    finally
      F.Free;
    end;
  end;    end;