如何在自定义渲染器中更新向左/向右滑动手势内网格的BindingContext？

// 自定义渲染器
public class CustomRenderer : ViewRenderer<CustomControl, UIView>
{
    protected override void OnElementChanged(ElementChangedEventArgs<CustomControl> e)
    {
        base.OnElementChanged(e);

        if (Control == null)
        {
            // 创建原生控件
            var nativeControl = new UIView();

            // 添加向左/向右滑动手势
            var swipeGesture = new UISwipeGestureRecognizer(HandleSwipe);
            swipeGesture.Direction = UISwipeGestureRecognizerDirection.Left | UISwipeGestureRecognizerDirection.Right;
            nativeControl.AddGestureRecognizer(swipeGesture);

            SetNativeControl(nativeControl);
        }
    }

    private void HandleSwipe(UISwipeGestureRecognizer gestureRecognizer)
    {
        if (gestureRecognizer.State == UIGestureRecognizerState.Ended)
        {
            // 获取手势方向
            var direction = gestureRecognizer.Direction;

            // 更新网格的BindingContext
            var grid = Element.Grid;
            if (direction == UISwipeGestureRecognizerDirection.Left)
            {
                grid.BindingContext = new LeftViewModel();
            }
            else if (direction == UISwipeGestureRecognizerDirection.Right)
            {
                grid.BindingContext = new RightViewModel();
            }

            // 通知自定义控件进行UI更新
            Element.InvalidateMeasure();
        }
    }
}

// 自定义控件
public class CustomControl : View
{
    public Grid Grid { get; set; }
}

// 网格的BindingContext对应的ViewModel
public class LeftViewModel
{
    // 左侧网格的数据和逻辑
}

public class RightViewModel
{
    // 右侧网格的数据和逻辑
}