Application-Session-Cookie

            //Application
            Application["Name"] = "lisi";
            string Result1 = Application["Name"].ToString();

            //Session
            //优点 使用简单,不仅能传递简单数据类型,还能传递对象.数据量大小是不限制的.存放在服务器端
            //缺点 在Session变量存储大量的数据会消耗较多的服务器资源.
            Session["name"] = "Value";
            string Result2 = Session["name"].ToString();
            //清空所有session对象的值，但保留会话
            Session.Clear();
            //调用clear()方法
            Session.RemoveAll();
            //删除某个session对象
            Session.Remove("name");
            //结束当前会话并删除所有session对象，并 调用Session_End方法（InProc模式下）。当下一个请求到来时将激发Session_Start方法。 Abandon方法用于主动结束会话，若没有调用该方法，当会话超时后，也会自动结束当前会话。
            Session.Abandon();

            //Cookie
            //比如我们建立一个名为user的cookie
            HttpCookie cookie = new HttpCookie("user");
            //赋值为Test
            cookie.Value = "Test";
            //设置Cookies有效期为1天.默认cookie在浏览器关闭的时候自动失效
            cookie.Expires = DateTime.Now.AddDays(1);
            //将Cookies存入
            Response.AppendCookie(cookie);
            //取出Cookie值
            HttpCookie cookieOne = Request.Cookies["user"];
            string cookieValue = cookieOne.Value;


            //一个Cookie中储存多个信息，比如我们在名为user1的cookie下加多个信息
            HttpCookie cookieTwo = new HttpCookie("user1");
            cookieTwo.Values.Add("name", "222");
            cookieTwo.Values.Add("pwd", "333");
            cookieTwo.Values.Add("member", "admin");
            Response.AppendCookie(cookieTwo);
            //从客户端获取取信息也一样简单
            HttpCookie cookie3 = Request.Cookies["cookieTwo"];
            string value1 = cookie3.Values["name"];
            string value2 = cookie3.Values["pwd"];

            HttpCookie aCookie = new HttpCookie("userInfo");
            aCookie.Values["userName"] = "patrick";
            aCookie.Values["lastVisit"] = DateTime.Now.ToString();
            aCookie.Expires = DateTime.Now.AddDays(1);
            Response.Cookies.Add(aCookie);

            //清除Cookie的正确代码（假设Cookie名称为UserInfo）：
            if (Request.Cookies["UserInfo"] != null)
            {
                Response.Cookies["UserInfo"].Expires = DateTime.Now.AddDays(-1);
            }
            //如果需要清除所有Cookie，则遍历：
            for (int i = 0; i < Response.Cookies.Count; i++)
            {
                Response.Cookies[i].Expires = DateTime.Now.AddDays(-1);
            }