Implement Itunes like "All" filter in master detail interface

Question

In Itunes, there is an "All" filter in the music browser. The user, e.g., can select "All (350 Artists)" to see music across all artists. I have a Core Data backed Master Detail interface where I have a list of groups as master and a list of items in the group as detail, both NSTableViews. I have connected the 2 views together through regular bindings on NSArrayControllers backed by Core Data. I want to add the "All" default option as the first row in my master NSTableView. Will I have to take over the data source function from Core Data in order to add this one item as the first row in my master table or is there a way to add it without sacrificing the free code I am getting from the bindings?

Answer 1

When I need to add an "All" option to any type of list or grid, I simply add it to the bound data set with a distinct value. For example, if I have a drop down list of Stores bound to the results of a query - I do this (in SQL server, syntax might be slightly different for CoreData):

select 0 StoreNumber, 'All' StoreName
union
select StoreNumber, StoreName from Stores

so the "All" entry becomes part of my bound data.

Ron