How to implement trigger (like content change) on an array

For example, I setup an array,

I need to raise an event or call a function automatically when any element of an array is changed. How can I do this?

There is no direct way for this. Create two properties that Add/Remove array elements and raise an event while doing so. Trap this event and do the needed stuff.

How to raise an event manually?

I just know adding stuff in system event .