Текст сообщения (Indy)

Проверяю все сообщения:
for i:=1 to IdPOP31.CheckMessages do
begin
IdMessage1.Clear;
IdPOP31.RetrieveHeader(i,IdMessage1);
..............
Выводит все нормально кроме самого текста сообщения:
Memo2.Lines.Add(' Текст сообщения : '+DecodeStr(IdMessage1.Body.Text));
.................
end;
Почему так получается?
Зависит ли IdMessage1.Body.Text от кодировки сообщения?



function DecodeStr(Text: string): string;
var
Temp, Dec: string;
P,P2:Integer;
begin
Temp:=Text;
Result:='';

while pos('=?windows-1251?',Temp)>0 do
begin
P:=pos('=?windows-1251?',Temp);
// P2:=pos('?=',Copy(Temp,P,Length(Temp)))+P;
P2:=pos('?=',Temp);
Dec:=Copy(Temp,p+17,P2-(P+17));
Dec:=Form1.IdDecoderMIME1.DecodeString(Dec);
Result:=Result+Copy(Temp,1,P-1)+Dec;
Temp:=Copy(Temp,P2+2,length(Temp));
end;
Result:=Result+Temp;
Temp:=Result;

Result:='';
while pos('=?koi8-r?',Temp)>0 do
begin
P:=pos('=?koi8-r?',Temp);
P2:=pos('?=',Temp);
Dec:=Copy(Temp,p+11,P2-(P+11));
try
if Dec<>''
then Dec:=KOI8_RToUTF16Str(Form1.IdDecoderMIME1.DecodeString(Dec));
except

end;
Result:=Result+Copy(Temp,1,P-1)+Dec;
Temp:=Copy(Temp,P2+2,length(Temp));
end;
Result:=Result+Temp;
end;


..................
function KOI8_RToUTF16Str(const s: string): WideString;
var
i,j: integer;
begin
j:= length(s);
setLength(Result,j);
for i:=1 to j do
Result:=KOI8_RToUTF16Char(s);
end;


........................


function KOI8_RToUTF16Char(const P: Char): WideChar;
begin
case ord(P) of
$80: result:= #$2500; $81: result:= #$2502; $82: result:= #$250c; $83: result:= #$2510; $84: result:= #$2514;
$85: result:= #$2518;
$86: result:= #$251c;
$87: result:= #$2524;
$88: result:= #$252c;
$89: result:= #$2534;
$8a: result:= #$253c;
$8b: result:= #$2580; $8c: result:= #$2584; $8d: result:= #$2588; $8e: result:= #$258c; $8f: result:= #$2590; $90: result:= #$2591; $91: result:= #$2592; $92: result:= #$2593; $93: result:= #$2320; $94: result:= #$25a0; $95: result:= #$2219; $96: result:= #$221a; $97: result:= #$2248; $98: result:= #$2264; $99: result:= #$2265; $9a: result:= #$00a0; $9b: result:= #$2321;
$9c: result:= #$00b0; $9d: result:= #$00b2; $9e: result:= #$00b7; $9f: result:= #$00f7; $a0: result:= #$2550; $a1: result:= #$2551; $a2: result:= #$2552; $a3: result:= #$0451; $a4: result:= #$2553; $a5: result:= #$2554; $a6: result:= #$2555; $a7: result:= #$2556; $a8: result:= #$2557; $a9: result:= #$2558; $aa: result:= #$2559; $ab: result:= #$255a; $ac: result:= #$255b; $ad: result:= #$255c; $ae: result:= #$255d; $af: result:= #$255e; $b0: result:= #$255f; $b1: result:= #$2560; $b2: result:= #$2561; $b3: result:= #$0401; $b4: result:= #$2562; $b5: result:= #$2563; $b6: result:= #$2564;
$b7: result:= #$2565;
$b8: result:= #$2566; $b9: result:= #$2567;
$ba: result:= #$2568;
$bb: result:= #$2569; $bc: result:= #$256a; $bd: result:= #$256b;
$be: result:= #$256c; $bf: result:= #$00a9; $c0: result:= #$044e; $c1: result:= #$0430; $c2: result:= #$0431; $c3: result:= #$0446; $c4: result:= #$0434; $c5: result:= #$0435; $c6: result:= #$0444; $c7: result:= #$0433; $c8: result:= #$0445; $c9: result:= #$0438; $ca: result:= #$0439; $cb: result:= #$043a; $cc: result:= #$043b; $cd: result:= #$043c; $ce: result:= #$043d; $cf: result:= #$043e; $d0: result:= #$043f; $d1: result:= #$044f; $d2: result:= #$0440; $d3: result:= #$0441; $d4: result:= #$0442; $d5: result:= #$0443; $d6: result:= #$0436; $d7: result:= #$0432; $d8: result:= #$044c; $d9: result:= #$044b; $da: result:= #$0437; $db: result:= #$0448; $dc: result:= #$044d; $dd: result:= #$0449; $de: result:= #$0447; $df: result:= #$044a; $e0: result:= #$042e; $e1: result:= #$0410; $e2: result:= #$0411; $e3: result:= #$0426; $e4: result:= #$0414; $e5: result:= #$0415; $e6: result:= #$0424; $e7: result:= #$0413; $e8: result:= #$0425; $e9: result:= #$0418; $ea: result:= #$0419; $eb: result:= #$041a; $ec: result:= #$041b; $ed: result:= #$041c; $ee: result:= #$041d; $ef: result:= #$041e; $f0: result:= #$041f; $f1: result:= #$042f; $f2: result:= #$0420; $f3: result:= #$0421; $f4: result:= #$0422; $f5: result:= #$0423; $f6: result:= #$0416; $f7: result:= #$0412; $f8: result:= #$042c; $f9: result:= #$042b; $fa: result:= #$0417; $fb: result:= #$0428; $fc: result:= #$042d; $fd: result:= #$0429; $fe: result:= #$0427; $ff: result:= #$042a;
else result:=WideChar(ord(P));
end;
end;