Those methods are good if all of the items are being unloaded but in the program I am working on, pictureboxes etc are not unloaded according to any pattern.

So I might have 10 picture boxes but unload 1, 4 and 9.

Later on, I may need to add new ones or remove the rest. Do I just need to keep some way of tracking what's been loaded? eg in an array that lists the index numbers of the unloaded pages?