I have an architectural question concerning the use of sets of data providers for a Tree control.
We have a master list of Users for our chat application, which we might need to filter and sort in various ways (buddies only, blocked only, etc). For our buddy list, we were using an adapter-esque solution to convert the list of users into a list of "buddy groups" containing User objects underneath them. We recently stumbled across the HierarchicalCollectionView and GroupingCollection objects and decided those might be better than the overhead of a custom adapter class, but we're having some trouble getting everything to sync up correctly. We used the tutorial here to try to set up our collections correctly: http://blog.tsclausing.com/post/20. Essentially, we have a list of Users that is shared throughout the application. In our BuddyList view, we have a ListCollectionView with list = masterUserList, with a sort and filter applied as well. We then have a GroupingCollection sorting on the User's groupName field. We then have a HierarchicalCollectionView adapting the GroupingCollection for display in a Tree control. We see the data as expected, but we're having trouble figuring out exactly how to keep everything in lock-step. Sometimes properties of the User object change completely asynchronously -- if a User signs off, we update their online status and need to reapply the sort on our ListCollectionView, but we don't have a specific request/response, so we can't rely on a command or delegate or anything. If we update the model, it fires a COLLECTION_CHANGE event, but this doesn't seem to fire every time in the bound ListCollectionView. We anticipated this event would fire in the bound object as well, allowing us to call refresh and invalidateDisplayList as necessary. Has anyone else used chained collections/views in this manner? I think in general we're trying to figure out exactly how to set up refreshes and redraws that aren't directly tied to button/column clicks (as in every other application we come across). Thanks!
