When do I need to incorporate Dispose into my code?

Question

I'm trying to understand (a) if I ever need to implement Dispose in my classes and (b) if I do, when do I?
Part of the reason for asking is because I have implemented Dispose in some of my classes, because I wanted to ensure that collections of items were being correctly cleaned up when I didn't need them any longer, but navigating away from pages that results
in a lot of items being disposed is causing the app to "lock up" for some time.
What is the best practice guidance and advice, please? From what I've read, it looks like Store apps *don't* generally need to Dispose, even though they are built on top of .NET and .NET *does* need Dispose.
Thanks.

Answer 1

I need to drill into the whole "do I need to unhook from events" a bit more because I'm getting very confused as to when I need to and when I don't. Here are a couple of examples:
1. I have a class called RHObjectFile and it defines the following:
publicstaticeventEventHandlerFileChangedEvent;
and some other classes (e.g. RHIndividualRecord) where the constructor includes:
RHObjectFile.FileChangedEvent += HandleFileChangeEvent;
So, given that arrangement, do I need to unhook from FileChangedEvent in order for GC to realise that an instance of RHIndividualRecord is no longer in use? If GC gets rid of an instance of RHIndividualRecord, does it automatically (magically) unhook from
event handlers?
2. Pages typically have something like the following in their constructor:
this.navigationHelper =
newNavigationHelper(this);
this.navigationHelper.LoadState +=
navigationHelper_LoadState;this.navigationHelper.SaveState
+= navigationHelper_SaveState;
Again, do I need to unhook from LoadState/SaveState in order to allow GC to clean up the Page instance when it isn't in use any more?
Thanks.