Asp.net authenticate user manually in code

in my asp.net mvc project i added facebook authentication to my project. I also save the facebook users in my database too. I have default asp.net authentication system for my site. When a facebook user give permission to my facebook application i get facebook user information like name,id and sa开发者_运维知识库ve them to my User table in my database, also give them a new guid for Id column. Then set them authenticated like below

public ActionResult FbInit()
    {
        FacebookApp app = new FacebookApp();

        if (app.Session != null)
        {
            dynamic parameters = new ExpandoObject();
            parameters.fields = "id,name";
            dynamic result = app.Api("me", parameters);

            string id = result.id;
            string name = result.name;

            using (TestDbEntities context = new TestDbEntities())
            {
                AuthTestAjax.Models.User newUser;
                if (null == (newUser = context.Users.Where(p => p.FbId == id).FirstOrDefault()))
                {
                    newUser = new User();
                    newUser.Id = Guid.NewGuid();
                    newUser.Name = name;
                    newUser.FbId = id;
                    context.AddToUsers(newUser);
                    context.SaveChanges();
                }

                System.Web.Security.FormsAuthentication.SetAuthCookie(newUser.Id.ToString(), false);
            }

        }


        return Json("");
    }

-I make persistent cookie false because i dont know when they will logout from facebook.

When user comes again to my site (he also login facebook), i want him to be authenticated. But how can i do that ?

I am trying to set HttpContext.Current.User but i am not sure that i am on the right way, help me about this situation.

I am trying this.

        public ActionResult AuthBox()
    {
        if (HttpContext.User.Identity.IsAuthenticated)
            return View("AuthBox");

        FacebookApp app = new FacebookApp();

        if (app.Session != null)
        {
            HttpContext.User   // <== Can I set this here to authenticate user?
            return View("AuthBox");
        }

        return View("AnonyBox");
    }

---

You will need to do FormsAuthentication.SetAuthCookie again when your app identifies the facebook user.

        FacebookApp app = new FacebookApp();

        if (app.Session != null)
        {
            FormsAuthentication.SetAuthCookie(app.Session.Username /*Or wherever you get it*/, false);
            return View("AuthBox");
        }

You cannot set HttpContext.User manually.