public string RemoveHTMLTags(string htmlStream)

        {

            if (htmlStream == null)

            {

                throw new Exception("Your input html stream is null!");

                return null;

            }

            /*

             * 最好把所有的特殊HTML标记都找出来，然后把与其相对应的Unicode字符一起影射到Hash表内，最后一起都替换掉

             */

            //先单独测试,成功后,再把所有模式合并

            //注:这两个必须单独处理

            //去掉嵌套了HTML标记的JavaScript:(<script)[\\s\\S]*(</script>)

            //去掉css标记:(<style)[\\s\\S]*(</style>)

            //去掉css标记:\\..*\\{[\\s\\S]*\\}

            htmlStream = Regex.Replace(htmlStream, "(<script)[\\s\\S]*?(</script>)|(<style)[\\s\\S]*?(</style>)", " ", RegexOptions.IgnoreCase);

            //htmlStream = RemoveTag(htmlStream, "script");

            //htmlStream = RemoveTag(htmlStream, "style");

            //去掉普通HTML标记:<[^>]+>

            //替换空格:&nbsp;|&amp;|&shy;| |­

            htmlStream = Regex.Replace(htmlStream, "<[^>]+>|&nbsp;|&amp;|&shy;| |­|&bull;|&lt;|&gt;", " ", RegexOptions.IgnoreCase);

            //htmlStream = RemoveTag(htmlStream);

            //替换左尖括号

            //htmlStream = Regex.Replace(htmlStream, "&lt;", "<");

            //替换右尖括号

            //htmlStream = Regex.Replace(htmlStream, "&gt;", ">");

            //替换空行

            //htmlStream = Regex.Replace(htmlStream, "[\n|\r|\t]", " ");//[\n|\r][\t*| *]*[\n|\r]

            htmlStream = Regex.Replace(htmlStream, "(\r\n[\r|\n|\t| ]*\r\n)|(\n[\r|\n|\t| ]*\n)", "\r\n");

            htmlStream = Regex.Replace(htmlStream, "[\t| ]{1,}", " ");

            return htmlStream.Trim();

        }