去除HTML标记

        ///   <summary>
        ///   去除HTML标记
        ///   </summary>
        ///   <param   name="NoHTML">包括HTML的源码   </param>
        ///   <param   name="isClearSpechars">去除特殊字符   </param>
        ///   <returns>已经去除后的文字</returns>
        public static string NoHTML(string htmlstring, bool isClearSpechars = true)
        {
            if (String.IsNullOrEmpty(htmlstring))
            {
                return string.Empty;
            }

            //删除脚本
            htmlstring = Regex.Replace(htmlstring, @"<script[^>]*?>.*?</script>", "", RegexOptions.IgnoreCase);
            //删除HTML
            htmlstring = Regex.Replace(htmlstring, @"<(.[^>]*)>", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"([\r\n])[\s]+", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"-->", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"<!--.*", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"&(quot|#34);", "\"", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"&(amp|#38);", "&", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"&(lt|#60);", "<", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"&(gt|#62);", ">", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"&(nbsp|#160);", " ", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"&(iexcl|#161);", "\xa1", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"&(cent|#162);", "\xa2", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"&(pound|#163);", "\xa3", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"&(copy|#169);", "\xa9", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, @"&#(\d+);", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, "xp_cmdshell", "", RegexOptions.IgnoreCase);
            //删除与数据库相关的词--可以根据个人要求进行删除添加
            htmlstring = Regex.Replace(htmlstring, "select", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, "insert", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, "delete from", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, "count‘‘", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, "drop table", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, "truncate", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, "asc", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, "mid", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, "char", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, "xp_cmdshell", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, "exec master", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, "net localgroup administrators", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, "and", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, "net user", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, "or", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, "net", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, "*", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, "-", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, "delete", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, "drop", "", RegexOptions.IgnoreCase);
            htmlstring = Regex.Replace(htmlstring, "script", "", RegexOptions.IgnoreCase);
            if (isClearSpechars)
            {
                //特殊的字符
                htmlstring = htmlstring.Replace("<", "");
                htmlstring = htmlstring.Replace(">", "");
                htmlstring = htmlstring.Replace("*", "");
                htmlstring = htmlstring.Replace("-", "");
                htmlstring = htmlstring.Replace("?", "");
                htmlstring = htmlstring.Replace("‘", "‘‘");
                htmlstring = htmlstring.Replace(",", "");
                htmlstring = htmlstring.Replace("/", "");
                htmlstring = htmlstring.Replace(";", "");
                htmlstring = htmlstring.Replace("*/", "");
                htmlstring = htmlstring.Replace("\r\n", "");
            }
            htmlstring = System.Web.HttpUtility.HtmlEncode(htmlstring).Trim();
            return htmlstring;
        }