[ROOT] / doc / DocFrag / ARCCore.IP.OnTrySetP

ClassMemberAttribute

Event handler to be called by TrySetP before it changes a property value (but AFTER it has done any validity checks, that is, after it has 'decided' to return TRUE, in other words, event handler should be called when change is guaranteed to go through, but before it actually has been done).

Return value TRUE is to be treated as 'Cancel', that is, the change should not go through after all.

If implementing class does not support events it can implement this method as follows:
=> false;

Some uses for this event handler could be:
1) To record first instance of a value (the initial value).
For instance if a Customer can have subscriptions, you may want to note their initial subscription.
For instance, the first time a subscription it encountered, like 'Customer/42/Subscription = Premium', the event handler can
store 'Customer/42/InitialSubscription = Premium' in addition to the original change.

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Generated 2025-10-29 15:18:15.982 UTC