asp.net获取客户端ip

//获取客户端ip
private string GetClientIP()
  {
   string result = HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
   if (null == result || result == String.Empty)
   {
    result = HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];
   }
   if (null == result || result == String.Empty)
   {
    result = HttpContext.Current.Request.UserHostAddress;
   }
   return result;
  }