Excel VBA object constructor and destructor

vba object memory-leaks constructor destructor
notnot picture notnot · Feb 20, 2009 · Viewed 45.6k times · Source

I need to make some custom objects in VBA that will need to reference each other and I have a some issues.

First - how do object constructors work in VBA? Are there constructors?

Second - are there destructors? How does VBA handle the end of the object lifecycle? If I have an object that references others (and this is their only reference), then can I set it to Nothing and be done with it or could that produce memory leaks?

This quasi-OO stuff is just a little bit irritating.

Answer

Will Rickards picture Will Rickards · Feb 20, 2009

VBA supports Class Modules. They have a Class_Initialize event that is the constructor and a Class_Terminate that is the destructor. You can define properties and methods. I believe VBA uses reference counting for object lifecycle. Which is why you see a lot of Set whatever = Nothing in that type of code. In your example case I think it will not leak any memory. But you need to be careful of circular references.

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