WP7 app, MethodAccessException on WP7 device but works fine on WP8 device

Question

Pretty much as the title says, I have a wp7 app that when deployed and debugged on a WP7 device (lumia 800) I get a MethodAccessException when using the Facbook c# SDK but deploy and debug on a WP8 device (lumia 920) it works fine. Here is where the error occoucrs

private Uri GetURLLogin()
{     
  var fb = FacebookClient();
  return fb.GetLoginUrl(
       new {
            client_id = "blahblah",
            redirect_uri = "http://www.facebook.com/connect/login_success.html",
            response_type = "token",
            display = "popup",
            scope = "user_birthday, email"
           });   // Error occurs here
}

Answer 1

Due to security reasons Facebook.dll cannot access anonymous object properties.

Try adding

[assembly: InternalsVisibleTo("Facebook")]

This is mentioned in the FAQ at http://facebooksdk.net/docs/faq/

Answer 2

Try this

   private Uri GetFacebookLoginUrl(string appId, string extendedPermissions)
    {
        var fb = FacebookClient();
        var parameters = new Dictionary<string, object>();
        parameters["client_id"] = appId;
        parameters["redirect_uri"] = "https://www.facebook.com/connect/login_success.html";
        parameters["response_type"] = "token";
        parameters["display"] = "touch";

        // add the 'scope' only if we have extendedPermissions.
        if (!string.IsNullOrEmpty(extendedPermissions))
        {
            // A comma-delimited list of permissions
            parameters["scope"] = extendedPermissions;
        }

        return _fb.GetLoginUrl(parameters);

    }

You Need to Give App ExtendedPermissions

 private const string ExtendedPermissions = "user_about_me,read_stream,publish_stream,user_events,offline_access,user_activities,user_interests,user_likes,email,friends_birthday";

And Your App Key Generated By Facebook