# `BCCollectionViewDelegate collectionView:viewControllerBecameInvisible:`

*Instance Method*

## Declaration

```swift
optional func collectionView(_ collectionView: BCCollectionView!, viewControllerBecameInvisible viewController: NSViewController!)
```

```objc
- (void) collectionView:(BCCollectionView *) collectionView viewControllerBecameInvisible:(NSViewController *) viewController;
```

```python
collectionView_viewControllerBecameInvisible_(collectionView: BCCollectionView, viewController: NSViewController)
```