正则表达式过滤html标签对

public string DealHtml(string str)
    {
        //str = Regex.Replace(str, @"\<(img)[^>]*>|<\/(img)>", "", RegexOptions.IgnoreCase);
        str = Regex.Replace(str, @"\<(table|tbody|tr|td|th)[^>]*>|<\/(table|tbody|tr|td|th)>", "", RegexOptions.IgnoreCase);
        str = Regex.Replace(str, @"\<(div|blockquote|fieldset|legend)[^>]*>|<\/(div|blockquote|fieldset|legend)>", "", RegexOptions.IgnoreCase);
        //str = Regex.Replace(str, @"\<(font|i|u|h[1-9]|s)[^>]*>|<\/(font|i|u|h[1-9]|s)>", "", RegexOptions.IgnoreCase);
        //str = Regex.Replace(str, @"\<(style|strong)[^>]*>|<\/(style|strong)>", "", RegexOptions.IgnoreCase);
        //str = Regex.Replace(str, @"\<a[^>]*>|<\/a>", "", RegexOptions.IgnoreCase);
        //str = Regex.Replace(str, @"\<(meta|iframe|frame|span|tbody|layer)[^>]*>|<\/(iframe|frame|meta|span|tbody|layer)>", "", RegexOptions.IgnoreCase);
        str = Regex.Replace(str, @"\<br[^>]*", "", RegexOptions.IgnoreCase);
        str = str.Replace("<br>", "");
        return str;
    }