private void SetupCollectionView()
{
_source = new AddPostCollectionSource(ImageCollection, SelectedImageCell.Identifier, new WeakReference <AddPostView>(this));
ImageCollection.RegisterClassForCell(typeof(SelectedImageCell), SelectedImageCell.Identifier);
var collectionLayout = new SpacingCollectionFlowLayout {
ItemSize = new CGSize(100, 110),
};
ImageCollection.CollectionViewLayout = collectionLayout;
ImageCollection.Source = _source;
}