正则表达式之提取括号内内容

  string str="aaaaaaaaa(bbbb)cccc";     
  var patern = "(?<=\\()[^\\)]+";
  if (Regex.Matches(item.OuterHtml, patern).Count > 0)
  {
     foreach (var regex in Regex.Matches(item.OuterHtml, patern))
      {
       str += regex;
      }
  }
    console.writerLine(str);