asp.net防止sql注入，删除关键字的一个重要方法

/// <summary>

    /// 去除HTML标记

    /// </summary>

    /// <param name="NoHTML">包括HTML的源码 </param>

    /// <returns>已经去除后的文字</returns>

    public static string NoHTML(string Htmlstring)

    {

        if (Htmlstring == null)

        {

            return "";

        }

        else

        {

            //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 

            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);

            //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("\r\n", "");

            Htmlstring = HttpContext.Current.Server.HtmlEncode(Htmlstring).Trim();

            return Htmlstring;

        }

    }