多字节和Unicode编码是不可逆的

procedure TForm1.Button1Click(Sender: TObject);
var
LStr, LStr2: string;
LWideString: WideString;
LLen: Integer;
I: Integer;
begin
SetLength(LStr, 256);
for I := 1 to Length(LStr) do
LStr[I] := Char(Random(256));
SetLength(LWideString, Length(LStr));
LLen := MultiByteToWideChar(GetACP, 0, @LStr[1], Length(LStr), @LWideString[1], Length(LWideString));
SetLength(LWideString, LLen);

SetLength(LStr2, Length(LStr));
LLen := WideCharToMultiByte(GetACP, 0, @LWideString[1], Length(LWideString), @LStr2[1], Length(LStr2), nil, nil);
SetLength(LStr2, LLen);
for I := 1 to Length(LStr) do
begin
if LStr[I] <> LStr2[I] then
begin
ShowMessage('e');
end;
end;
end;