OpenId - how to use checkid_immediate and x-has-session?

The documentation doesn't tell much about those two parameters. I understand they somehow related to log in status checking.

I want to check if a user is currently logged in the browser (Meaning, signed in with google, and checked "keep me logged in" )

I want to be able to differentiate between to states :

1. A user is logged in the browser (meaning, signed in with Google for example, and check "Keep me logged in") and that user already approved my app.

2. Any other state. (user is not logged in . user logged in but with an identity he didn't approved yet... etc.)

If I know I am in the first state, I don't need to "show" the popup (I give it top=9999 left=9999)

I am trying to figure out the two states with this code. This needs to be done without any user interaction or any visual cue.

public partial class WebForm1 : System.Web.UI.Page
    {
        protected string Url { get; set; }

        protected void Page_Load(object sender, EventArgs e)
        {
            var parameters = new Dictionary<string, string>();

            parameters.Add("openid.ns", "http://specs.openid.net/auth/2.0");
            parameters.Add("openid.claimed_id", "http://specs.openid.net/auth/2.0/identifier_select");
            parameters.Add("openid.identity", "http://specs.openid.net/auth/2.0/identifier_select");
            parameters.Add("openid.return_to", "http://localhost:17556/redirect.aspx");
            parameters.Add("openid.realm", "http://localhost:17556/");
            parameters.Add("openid.mode", "checkid_immediate");
            parameters.Add("openid.ns.ax", "http://openid.net/srv/ax/1.0");
            parameters.Add("openid.ax.mode", "fetch_request");
            parameters.Add("openid.ax.type.email", "http://axschema.org/contact/email");
            parameters.Add("openid.ax.required", "email");
            parameters.Add("openid.ns.ui", "http://specs.openid.net/extensions/ui/1.0"开发者_JAVA百科);
            parameters.Add("openid.ui.mode", "x-has-session");

            string OpenIdEndpoint = https://www.google.com/accounts/o8/ud;

            var url = CreateUrlRequest(OpenIdEndpoint, parameters);

            WebClient wc = new WebClient();
            var res = wc.UploadString(url, "");
        }


        public string CreateUrlRequest(string i_Url, Dictionary<string, string> i_Parameters)
        {
            return string.Format("{0}?{1}", i_Url, string.Join("&", i_Parameters.Select(kvp => string.Format("{0}={1}", kvp.Key, kvp.Value)).ToList()));
        }
    } 

running this code, a callback is sent to redirect.aspx, but the query string doesn't have any information about the states I am interested in. It contains openid.mode=setup_needed among other things.