開啟檔案，若失敗就跳出選擇關聯程式清單

  if OpenDialog1.execute then
  begin
  if ShellExecute(handle, 'Open', PChar(OpenDialog1.FileName), nil, nil, SW_NORMAL) = SE_ERR_NOASSOC then
    ShellExecute(GetDesktopWindow, nil, 'RUNDLL32.EXE',
      PChar('shell32.dll, OpenAs_RunDLL ' + OpenDialog1.FileName),
      PChar(ExtractFilePath(ParamStr(0))), SW_NORMAL);
  end;