AutoScrolling.cs

private UIScrollView _scrollView;
private UIView _contentView;

public override void ViewDidLoad()
{
    base.ViewDidLoad();

    _scrollView = new UIScrollView
        {
            ShowsHorizontalScrollIndicator = false,
            TranslatesAutoresizingMaskIntoConstraints = false
        };
    _contentView = new UIView { TranslatesAutoresizingMaskIntoConstraints = false };
    var subviews = View.Subviews.ToArray();
    var constraints = View.Constraints.Select(constraint => NSLayoutConstraint.Create(
        constraint.FirstItem == View ? _contentView : constraint.FirstItem,
        constraint.FirstAttribute,
        constraint.Relation,
        constraint.SecondItem == View ? _contentView : constraint.SecondItem,
        constraint.SecondAttribute,
        constraint.Multiplier,
        constraint.Constant)).ToArray();
    View.RemoveConstraints(View.Constraints);
    Array.ForEach(subviews, view => view.RemoveFromSuperview());
    _contentView.AddSubviews(subviews);
    _scrollView.Add(_contentView);
    _contentView.AddConstraints(constraints);
    Add(_scrollView);

    var edges = new[]
    {
        NSLayoutAttribute.Top,
        NSLayoutAttribute.Bottom,
        NSLayoutAttribute.Left,
        NSLayoutAttribute.Right
    };

    View.AddConstraint(NSLayoutConstraint.Create(View, NSLayoutAttribute.Width, NSLayoutRelation.Equal,
        _contentView, NSLayoutAttribute.Width, 1, 0));
    _scrollView.AddConstraints(
        edges.Select(
            edge => NSLayoutConstraint.Create(_scrollView, edge, NSLayoutRelation.Equal, _contentView, edge, 1, 0))
            .ToArray());
    View.AddConstraints(
        edges.Select(
            edge => NSLayoutConstraint.Create(View, edge, NSLayoutRelation.Equal, _scrollView, edge, 1, 0))
            .ToArray());
}

Sorry I missed this notification. This code will take the views that are currently in your ViewController and move them into a ScrollView. So yes, add the elements first. Should work as a base class, too.