Unwind from CollectionViewController/TablewViewController source class

Hello,
I have created source class (UICollectionViewSource) which I am using for CollectionViewController. I would like to call unwind action, whenever the image is selected.

In my CollectionViewCell class, I have itemSelected method:

    public override void ItemSelected(UICollectionView collectionView, NSIndexPath indexPath)
    {
        imageObject.Image = imageList[indexPath.Row];
        //NavigationController.PopViewController(true);
    }

In this method, I would need to return back to previous viewController. Unfortunately NavigationController.PopViewController(true); does not work here, as NavigationController does not exists in source class.

Is there any method which would call my NavigationController? Here I am using CollectionViewController, but I believe the same applies for TableViewController.

Thanks