这样吧:
TStringPacket = record
case integer of
0 String_Part: Array[0..23] of Char);
1 CharArray1: Array[0..5] of Char;
CharArray2: Array[0..5] of Char;
CharArray3: Array[0..5] of Char;
CharArray4: Array[0..5] of Char);
end;
var
p: ^TStringPacket;
begin
New(p);
ZeroMemory(p,SizeOf(TStringPacket));
p^.String_Part:='aaaaaabbbbbbccccdddd';
Showmessage(String(p^.CharArray1));
Showmessage(String(p^.CharArray2));
Showmessage(String(p^.CharArray3));
Showmessage(String(p^.CharArray4));
Dispose(p);
end;