How to programmatically trigger a goal to contact and then retrieve it in the same visit and in later visits

Question

I want to trigger a goal programmatically to the website visitor/contact and retrieve this triggered goal during the contact's current visit and in his future visits. I could trigger the goal of using CurrentPage.Register() method under Analytics.Tracker API, but how can I retrieve this goal in the same session and future sessions?

Please help. Thanks!

EDIT: It is not clear how to check whether the current contact is a new contact or an existing contact. Looks like Sitecore.Analytics.Tracker.Current.Contact.IsNew behaves inconsistently

Answer 1

Goals of the current visit (interaction) are stored in the session and can be retrieved using Tracker API:

List<PageEventData> pageGoals = Sitecore.Analytics.Tracker.Current.Interaction.Pages
                                .SelectMany(p => p.PageEvents)
                                .Where(evt => evt.IsGoal)
                                .ToList();

To retrieve goals of previous interactions you can use xConnect (SE question that you mentioned) or KeyBehaviourCache:

IReadOnlyCollection<KeyBehaviorCacheEntry> contactGoals = Sitecore.Analytics.Tracker.Current.Contact.KeyBehaviorCache.Goals;

If you want to personalize based on the fact that a specific goal was triggered during current or past interactions consider using Sitecore rules condition: /sitecore/system/Settings/Rules/Definitions/Elements/Visit/Goal was triggered during a past or current interaction