delphi TMemo和unicode

uses

  IdCoderHeader;

procedure TForm1.convertbuttonclick(Sender: TObject);

var

  s, s2 : string;

begin

  s := Memo1.Lines[0]; // '=?UTF-8?B?5aaC5L2V6K6TIGFydC1tYXRlIOaIkOeCug==?='

  s2 := DecodeHeader(s);

  Memo2.Text := s2;

end;