private void CreateConstraints() { CollectionViewConstraintHeight = NSLayoutConstraint.Create(CollectionView, NSLayoutAttribute.Height, NSLayoutRelation.Equal); CollectionViewConstraintHeight.Constant = 0; CollectionView.AddConstraint(CollectionViewConstraintHeight); AddConstraints(new[] { ImageCropViewConstraintTop = NSLayoutConstraint.Create(ImageCropView, NSLayoutAttribute.Top, NSLayoutRelation.Equal, this, NSLayoutAttribute.Top, 1, 0), MovieViewConstraintTop = NSLayoutConstraint.Create(MovieView, NSLayoutAttribute.Top, NSLayoutRelation.Equal, this, NSLayoutAttribute.Top, 1, 0), CollectionViewConstraintTop = NSLayoutConstraint.Create(CollectionView, NSLayoutAttribute.Top, NSLayoutRelation.Equal, ImageCropView, NSLayoutAttribute.Bottom, 1, 0) }); this.AddConstraints( ImageCropView.Height().EqualTo().WidthOf(ImageCropView), ImageCropView.AtLeftOf(this), ImageCropView.AtRightOf(this), MovieView.Height().EqualTo().WidthOf(MovieView), MovieView.AtLeftOf(this), MovieView.AtRightOf(this), CollectionView.AtBottomOf(this), CollectionView.AtLeftOf(this), CollectionView.AtRightOf(this) ); }