iphone - 带有 NSManaged 对象的搜索栏

Question

- (void)filterContentForSearchText:(NSString*)searchText scope:(NSString*)scope
{
    NSPredicate *resultPredicate = [NSPredicate 
                                predicateWithFormat:@"SELF contains[cd] %@",
                                searchText];

    searchResultContacts = [contactArray filteredArrayUsingPredicate:resultPredicate];
}

如果 contactArray 包含 MSManaged 对象，如何获得结果