XAML GettingFocus ArgumentException

Question

我们正在尝试使用GettingFocus将焦点从祖先控件重定向到子节点，但我们看到ArgumentExceptions在某些情况下被抛出。

到目前为止我注意到的案例：

1. NewFocusedElement的ActualHeight或ActualWidth为0
2. NewFocusedElement无法获得焦点

无论如何都要保护args.NewFocusedElement = element; ？

我们将异常作为临时解决方案。

以下是代码：

private void OnGettingFocus(UIElement sender, GettingFocusEventArgs args)
        {
            if ((args.Direction == FocusNavigationDirection.Up || args.Direction == FocusNavigationDirection.Down)
                && (sender == this) && (DefaultFocusButton != null))
                // Add extra guard here so that the try / catch is no longer needed
            {
                try
                {
                    args.NewFocusedElement = DefaultFocusButton;
                }
                catch (ArgumentException e)
                {
                    // This focus redirect causes an exception when the element can't receive focus
                }
            }
        }