asp.net保存登录状态

 用session 相对cookies而言安全点，但是回存在失效为题

这里介绍下cookies的简单用法

　　　　　　  //声明、写入cookies
            HttpCookie cookie = new HttpCookie("UserName");  
            cookie.Value = name;
            if (Convert.ToInt32(this.ddlDate.SelectedValue) <31)
            {
                cookie.Expires = DateTime.Today.AddDays(Convert.ToInt32(this.ddlDate.SelectedValue));
            }
            else
            {
                cookie.Expires = DateTime.Today.AddHours(Convert.ToInt32(this.ddlDate.SelectedValue));
            }
            //这句不能丢
            Response.Cookies.Add(cookie);

读取cookies

 if (Request.Cookies["UserName"]!=null)
            {
                this.lblWelcome.Text = Request.Cookies["UserName"].Value + "，欢迎来到尊贵商城！";
                this.pnlWelcome.Visible = true;
                this.pnlLogout.Visible = true;
                this.pnlLogin.Visible = false;
            }