# `BCCollectionViewDelegate collectionView:didDoubleClickViewControllerAtIndex:`

*Instance Method*

## Declaration

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

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

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