Using SelectionInList with SortedCollection?

Question

Using Visualworks (Cincom Smalltalk), and a List widget, how does one use a SortedCollection along with SelectionInList? For instance, how do I initialize a SelectionInList with a SortedCollection?

I'm confused about the process, and I can't find any good documentation about how to proceed.

Answer 1

just like that:

aSelectionInList list: aSortedCollection.

the selection in list is an object that manages a selection and a list, it doesn't actually care too much about what kind of collection you pass as a list, as long as it is sequencable (ie responds to #at:)

Answer 2

You really want to use List all the time in SelectionInList objects. The reason is that List manages its dependencies itself in an instance variable. Other kinds of collections manage their dependencies using a system-wide Dependencies collection. This means that if your window shuts down unexpectedly you could be left with garbage in the Dependencies collection that still holds onto your entire Window structure and prevents it from being garbage collected. I've seen images grow to huge sizes because of this.

If you use a List, you can always sort it in place by using the sort or sort: methods. If you ever need to add elements to the list, you can just add them at the end and re-sort.