gistfile1.cs

private NSObject _notification;
private float _scrollAmount;
private double _animationDuration;
private UIViewAnimationCurve _animationCurve;

public override void ViewDidLoad()
{
    ...
    
    _notification = UIKeyboard.Notifications.ObserveWillShow((s, e) =>
    {
        _animationDuration = e.AnimationDuration;
        _animationCurve = e.AnimationCurve;

        var r = UIKeyboard.FrameBeginFromNotification(e.Notification);
        _scrollAmount = r.Height;
        ScrollTheView(true);
    });
}

private void ScrollTheView(bool scale)
{
    UIView.BeginAnimations(string.Empty, IntPtr.Zero);
    UIView.SetAnimationDuration(_animationDuration);
    UIView.SetAnimationCurve(_animationCurve);

    var frame = View.Frame;

    if (scale)
        frame.Height -= _scrollAmount;
    else
        frame.Height += _scrollAmount;
    View.Frame = frame;
    UIView.CommitAnimations();
}