gistfile1.m

NSTableView *documenstTable;

-(IBAction)changeDisplayedKey:(id)sender {
  NSString *newValue = [[sender selectedItem] title];
  NSTableColumn *column = [documentsTable tableColumnWithIdentifier:@"OID"];

  /* Replace title: works just fine */
  [[column headerCell] setStringValue:newValue];

  /* Bind to the new keyPath */
  /* data is an NSDictionary */
  NSString *newKeyPath = [@"arrangedObjects.data." stringByAppendingString:newValue];
  NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithBool:YES], NSRaisesForNotApplicableKeysBindingOption,
                          [NSNumber numberWithBool:YES], NSCreatesSortDescriptorBindingOption,
                          nil];
  [[column dataCell] bind:@"value"
                 toObject:documentsArrayController
              withKeyPath:newKeyPath
                  options:options];
  [documentsTable reloadData];
}