/// 
        /// 获取客户端IP地址（无视代理）        /// 
        /// 
     
      若失败则返回回送地址
             public static string GetWebClientIp()        {            string userHostAddress = HttpContext.Current.Request.UserHostAddress;            if (HttpContext.Current.Request.ServerVariables["HTTP_VIA"] != null) // using proxy             {                userHostAddress = HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"].ToString(); // Return real client IP.             }             if (string.IsNullOrEmpty(userHostAddress))            {                userHostAddress = HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];            }            //最后判断获取是否成功，并检查IP地址的格式（检查其格式非常重要）            if (!string.IsNullOrEmpty(userHostAddress) && IsIP(userHostAddress))            {                return userHostAddress;            }            return "127.0.0.1";        }

/// 
        /// 检查IP地址格式        /// 
        ///         /// 
             public static bool IsIP(string ip)        {            return System.Text.RegularExpressions.Regex.IsMatch(ip,                @"^((2[0-4]\d|25[0-5]|[01]?\d\d?)\.){3}(2[0-4]\d|25[0-5]|[01]?\d\d?)$");        }