asp.net mvc中Forms身份验证身份验证流程

<system.web>
<authentication mode="Forms">
  <forms name="loginName" loginUrl="/UserInfo/login" cookieless="UseCookies" path="/" protection="All" timeout="30"></forms>
</authentication>
</system.web>

<modules>
  <!--<remove name="FormsAuthentication" />-->
</modules>

 public class UserInfoController : Controller //控制器
 {
 //身份验证过滤器
  [Authorize]
  public ActionResult Index()
  {
   return View();
  }
 }

   /// <summary>
  /// 用户登录
  /// </summary>
  /// <returns></returns>
  public ActionResult login()
  {
   return View();
  }  
  [HttpPost]
  public ActionResult login(loginModels login) {
   if (ModelState.IsValid)
   {
    var model = db.Admininfo.FirstOrDefault(a => a.AdminAccount == login.AdminAccount && a.AdminPwd == login.AdminPwd);
    if (model != null)
    {
     //存入票据（用户登录的时候去存信息，如果有信息直接去登录）
     var dtoModel = new Users
     {
      id = model.id,
      AdminPwd = model.AdminPwd,
      AdminAccount=model.AdminAccount
     };
     //调用
     SetAuthCookie(dtoModel);
     //获取登录地址
     var returnUrl = Request["ReturnUrl"];
     //判断登录地址是不是空值
     if (!string.IsNullOrWhiteSpace(returnUrl))
     {      
      return Redirect(returnUrl);
     }
     else
     {
      //return RedirectiToAction
      return Redirect("/Home/index");
     }

    }
    else
    {
     ModelState.AddModelError("", "账号密码不对");
     return View(login);
    }
   }
   else
   {
    ModelState.AddModelError("", "输入的信息有误");
    return View(login);

   }

  /// <summary>
  /// 对登录账号进行cookie
  /// </summary>
  /// <param name="model"></param>
  public void SetAuthCookie(Users loginModel) {
   //1、将对象转换成json
   var userdata = loginModel.ToJson();
   //2、创建票据FormsAuthenticationTicket
   FormsAuthenticationTicket ticket = new FormsAuthenticationTicket(2,"loginUser",DateTime.Now,DateTime.Now.AddDays(1), false, userdata);
   //对票据进行加密 
   var tickeEncrypt = FormsAuthentication.Encrypt(ticket);
   //创建Cookie，定义
   HttpCookie cookie = new HttpCookie(FormsAuthentication.FormsCookieName, tickeEncrypt);
   cookie.HttpOnly = true;
   cookie.Secure = FormsAuthentication.RequireSSL;
   cookie.Domain = FormsAuthentication.CookieDomain;
   cookie.Path = FormsAuthentication.FormsCookiePath;
   cookie.Expires = DateTime.Now.Add(FormsAuthentication.Timeout);
   //先移除cookie，在添加cookie
   Response.Cookies.Remove(FormsAuthentication.FormsCookieName);
   Response.Cookies.Add(cookie);
  } 

 public class loginModels
 {
  /// <summary>
  /// 账号
  /// </summary>
  [DisplayName("账号")]
  [Required(ErrorMessage = "账号不能为空")] 
  public string AdminAccount { get; set; }
  /// <summary>
  /// 密码
  /// </summary>
  [DisplayName("密码")]
  [Required(ErrorMessage = "密码不能为空")]
  public string AdminPwd { get; set; }
 }

protected void Application_AuthenticateRequest(object sender, EventArgs e)
  {
   //1、通过sender获取http请求
   // HttpApplication app = new HttpApplication();//实例化
   HttpApplication app = sender as HttpApplication;
   //2、拿到http上下文
   HttpContext context = app.Context;
   //3、根据FormsAuthe,来获取cookie
   var cookie = context.Request.Cookies[FormsAuthentication.FormsCookieName];
   if (cookie != null)
   {
    //获取cookie的值
    var ticket = FormsAuthentication.Decrypt(cookie.Value);
    if (!string.IsNullOrWhiteSpace(ticket.UserData))
    {
     //把一个字符串类别变成实体模型
     var model = ticket.UserData.ToObject<AdmininfoViewModel>();
     //var acount = model.AdminAccount; //获取账号
     context.User = new MyFormsPrincipal<AdmininfoViewModel>(ticket, model);
     //MyFormsPrincipal.Identity = new FormsIdentity(ticket);
     // MyFormsPrincipal.userdata;

    }
   }
  }

  /// <summary>
  /// 退出登录
  /// </summary>
  public ActionResult loginout()
  {
   //删除票据
   FormsAuthentication.SignOut();
   //清除cookie
   Response.Cookies[FormsAuthentication.FormsCookieName].Expires = DateTime.Now.AddDays(-1);
   Response.Cookies.Remove(FormsAuthentication.FormsCookieName);
   return RedirectToAction("Index", "Home");
 
  }

@Html.ActionLink("安全退出","loginout","Users")