Microsoft.Phone.Controls.ListPicker.OnListPickerModeChanged C# (CSharp) Method

        private void OnListPickerModeChanged(ListPickerMode oldValue, ListPickerMode newValue)
        {
            if ((ListPickerMode.Expanded == oldValue))
            {
                if (null != _page)
                {
                    _page.BackKeyPress -= OnPageBackKeyPress;
                    _page = null;
                }

                if (null != _frame)
                {
                    _frame.ManipulationStarted -= OnFrameManipulationStarted;
                    _frame = null;
                }
            }

            if (ListPickerMode.Expanded == newValue)
            {
                // Hook up to frame if not already done
                if (null == _frame)
                {
                    _frame = Application.Current.RootVisual as PhoneApplicationFrame;
                    if (null != _frame)
                    {
                        _frame.AddHandler(ManipulationStartedEvent, new EventHandler<ManipulationStartedEventArgs>(OnFrameManipulationStarted), true);
                    }
                }

                if (null != _frame)
                {
                    _page = _frame.Content as ListPickerPage;
                    if (null != _page)
                    {
                        _page.BackKeyPress += OnPageBackKeyPress;
                    }
                }
            }

            if (ListPickerMode.Full == oldValue)
            {
                ClosePickerPage();
            }
            if (ListPickerMode.Full == newValue)
            {
                OpenPickerPage();
            }

            SizeForAppropriateView(ListPickerMode.Full != oldValue);
            IsHighlighted = (ListPickerMode.Expanded == newValue);
        }