string StartsWith 方法 Https

 public ActionResult Index()
        {
            string url = "Https://www.baodu.com";
            bool isOK = false;
            if (url.StartsWith("https", StringComparison.OrdinalIgnoreCase))//使用序号排序规则并忽略大小写
            {
                isOK = true;
            }
            return View();
        }