获取客户端IP

  /// <summary>
        /// 获取用户IP地址
        /// </summary>
        /// <returns></returns>
        public static string GetClientIP()
        {

            string user_IP = string.Empty;
            if (System.Web.HttpContext.Current.Request.ServerVariables["HTTP_VIA"] != null)
            {
                if (System.Web.HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] != null)
                {
                    user_IP = System.Web.HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"].ToString();
                }
                else
                {
                    user_IP = System.Web.HttpContext.Current.Request.UserHostAddress;
                }
            }
            else
            {
                user_IP = System.Web.HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"].ToString();
            }
            return user_IP;
        }