判断请求是不是ajax

    public static bool IsAjaxRequest(HttpRequest request)
    {
        if (request == null)
        {
            throw new ArgumentNullException("request");
        }
        return ((request["X-Requested-With"] == "XMLHttpRequest") || ((request.Headers != null) && (request.Headers["X-Requested-With"] == "XMLHttpRequest")));
    }