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Description

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= 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).0x000D0x000A0x000D0x000AReturn value TRUE is to be treated as 'Cancel', that is, the change should not go through after all.0x000D0x000A0x000D0x000AIf implementing class does not desire to support this event it can implement this method as follows:0x000D0x000A  =0x003E false0x003B0x000D0x000A0x000D0x000ASome uses for this event handler could be:0x000D0x000A1) To record first instance of a value (the initial value).0x000D0x000AFor instance if a Customer can have subscriptions, you may want to note their initial subscription.0x000D0x000AFor instance, the first time a subscription is encountered, like 'Customer/42/Subscription = Premium', the event handler can0x000D0x000Astore 'Customer/42/InitialSubscription = Premium' in addition to the original change.0x000D0x000A0x000D0x000ANOTE: If you want more advanced capabilities you can use -EventSourcing- NOTE: with the help of -ARCEvent-.

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Generated 2026-06-10 09:09:47.625 UTC