错误的Unicode转换,如何在Delphi 2010源代码中存储重音字符并处理字符集？

var
  str: UnicodeString;
begin
  str := 'éàù';
  ShowMessage(str);
end;

var
  sl: TStringList;
begin
  sl := TStringList.Create;
  try
    sl.Text := 'éàù';
    sl.SaveToFile('output.txt', TEncoding.UTF8);
  finally
    sl.Free;
  end;
end;

var
  str: UnicodeString;
  enc: TEncoding;
  bytes: TBytes;
begin
  str := 'éàù';
  enc := TEncoding.UTF8;
  try
    bytes := enc.GetBytes(str);
    // 使用bytes进行处理
  finally
    enc.Free;
  end;
end;

var
  str: UnicodeString;
  fs: TFileStream;
begin
  str := 'éàù';
  fs := TFileStream.Create('output.txt', fmCreate);
  try
    fs.WriteBuffer(str[1], Length(str) * SizeOf(Char));
  finally
    fs.Free;
  end;
end;