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References in VB.Net
I want to pass a medium large Customer db object, but I don’t want to pass it by value, because I think it would be unnecessary.
In c++ when you had a large object it was inefficient to pass it by value, because a copy was created from it, so you passed it by reference so that there was no copy (of the object passed) created. I used to pass the parameter as a constant because that way if I tried to change the object inside the function the compiler wouldn’t let me so that I wouldn’t harm the passed object (because it was passed by reference). Is it possible to mimick this in vb.net or is it not needed?
My strong suspicion is that you’re getting confused about how values are passed in VB.
If your CustomerDb type is a class, then every expression of that type will have a value which is already a reference. By default, that reference will be passed by value – but it’s still only the reference which is passed, not a whole object.
If your CustomerDb type is a structure, then you really will be passing the whole value each time – and you should strongly consider changing it to a class anyway…
Of course, when you pass a reference by value, that doesn’t stop the object from being modified within the method, but it does mean that changes to the parameter variable itself aren’t reflected in the calling code.
Read my article on C# parameter passing – it’s much the same in VB.