Thread: Problem keeping track of instances

So, this is about C#?

Moved to the C# Programming forum.

Originally Posted by h3ro

What im looking for is a helper class with an interface for Adding and Removing and a way of changing the data of an instance in a way that I can make sure that the index or what ever I use to find the instance, always is the same instance.

I do not program in C#, but it seems to me that you just need to return a reference to the instance, which should mean just not returning a copy of the instance.

Yeah, something like a reference counter super(man)class would be useful.

Laserlight: C# does not pass structures as references and I cant use unsafe code.
Sipher: Im not sure if I understand, could you give a quick example or elaborate a bit further?

You could use a base class, superclass, from with to derive all the others.
That base class should include a reference counter variable as well as methods such as grab() and drop(). Each time you call grab, a pointer of that instance will be returned and the counter will be incremented. Each time you call drop the counter will be decremented. If the counter's value falls below one, the instance is destroyed.

Edit: And it's Sipher...

EditMore: I just noticed that my post may be irrelevant!...

OK...

I don't fully understand what you're asking. Let me suggest a solution, and you tell me why it wouldn't work.

Assuming your structure was named Struct, I'd use a SortedDictionary<Struct, [anything]> to store your instances. I'd use SortedDictionary instead of Dictionary because: 1) it's easier to write a comparer than it is to write a good override of GetHashCode, and 2) you can adjust the comparer to sort items into the order that you need. To get the array you need out of it, you copy SortedDictionary.Keys to an array.

Yeah, you should probably ignore my first post. I'm still a bit groggy.

What does it mean to "remove" an instance from your array? Do you have to shorten the array, copying all the instances into a new array? Similarly, do you have to grow your array to "add" an instance to it? If you're using an array, you probably shouldn't be adding or removing instances from it. That's a List<T>.