判断手机端还是pc端

 public static bool CheckIsMobile()
        {
            bool flag = false;
            string agent = SystemWeb.HttpContext.Current.Request.UserAgent;
            string[] keywords = { "Android", "iPhone", "iPod", "iPad", "Windows Phone", "MQQBrowser" };

            //排除 Windows 桌面系统
            if (!agent.Contains("Windows NT") || (agent.Contains("Windows NT") && agent.Contains("compatible; MSIE 9.0;")))
            {
                //排除 苹果桌面系统
                if (!agent.Contains("Windows NT") && !agent.Contains("Macintosh"))
                {
                    foreach (string item in keywords)
                    {
                        if (agent.Contains(item))
                        {
                            flag = true; 
                            break;
                        }
                    }
                }
            }
            return flag;
        }

 public ActionResult Login(string url)
        {
            if (CheckIsMobile())
            {
                return RedirectToAction("PhoneLogin");
            }
}