public static string FilterHtmlTag(string s)
{
 //<...>標(biāo)記正則表達(dá)式
 return Regex.Replace(s, @"<[^>]*>", delegate(Match match)
 {
  string v = match.ToString();
  //圖片,<p>,<br>正則表達(dá)式
  Regex rx = new Regex(@"^<(p|br|img.*)>$",
   RegexOptions.Compiled | RegexOptions.IgnoreCase); //
  if (rx.IsMatch(v))
  {
  return v; //保留圖片,<p>,<br>
  }
  else
  {
  return ""; //過(guò)濾掉
  }
 });
}

content = Regex.Replace(content, @"/\<span(\sclass\=\S*)*\>\S*\<\/span\>/g", "", RegexOptions.IgnoreCase);
content = Regex.Replace(content, @"<[^>]*>", "", RegexOptions.IgnoreCase);
content = content + "。。。";