I am using CoreData and have an Entity ContactList defined, which I created using the XCode xcdatamodel tool (or whatever you call that built-in thing:). I also set the Entity's Class name to "ContactList". I then used rentzsch's mogenerator (<http://github.com/rentzsch/mogenerator>) to generate my custom class files and added the simple method "toString" to my ContactList class.

The fetchedResultsController callback is pretty much standard and looks as follows:

```
- (NSFetchedResultsController *)fetchedResultsController {

if (fetchedResultsController_ != nil) {
    return fetchedResultsController_;
}
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"ContactList" inManagedObjectContext:self.managedObjectContext];
[fetchRequest setEntity:entity];
[fetchRequest setFetchBatchSize:20];
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"timeStamp" ascending:NO];
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil];
[fetchRequest setSortDescriptors:sortDescriptors];
NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:nil cacheName:@"Root"];
aFetchedResultsController.delegate = self;
self.fetchedResultsController = aFetchedResultsController;
[aFetchedResultsController release];
[fetchRequest release];
[sortDescriptor release];
[sortDescriptors release];

NSError *error = nil;
if (![fetchedResultsController_ performFetch:&error]) {
    NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
    abort();
}

return fetchedResultsController_;
}    

```

Now, when I start my application and try to call that method on a "ContactList" object, which in turn I get from a NSFetchedResultsController, I get 

```
ContactList *contactList = (ContactList *) [self.fetchedResultsController objectAtIndexPath:indexPath];
[contactList toString];    
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSManagedObject toString]: unrecognized selector sent to instance 0x6af7bf0'

```

As the message shows, somehow the NSFetchedResultsController does not return a "ContactList" object, but a more general NSManagedObject instead. 

Does anybody know why and how to resolve this???