spotlight issue

[davebenvenuti]

hey, i'm fairly new to cocoa/objective-c. i'm trying to write an app that finds files that were created or modified after the program has started. the following query works using mdfind:

(kMDItemContentType == 'public.xml') && (kMDItemFSContentChangeDate >= $time.now)

however, trying to use it as an NSPredicate for an NSMetadataquery in a cocoa app causes an exception to be thrown:

NSComparisonPredicate with right expression which is not NSConstantValueExpressionType given to NSMetadataQuery (kMDItemFSContentChangeDate >= $time.now)


any help would be greatly appreciated. thanks.