/// <summary>
/// 深度移除所有子项
/// </summary>
void ClearAllItems()
{
ClearItems(_owner.CenterItem);
ClearItems(_owner);
_owner.LeftAutoHide?.Items.Clear();
_owner.RightAutoHide?.Items.Clear();
_owner.TopAutoHide?.Items.Clear();
_owner.BottomAutoHide?.Items.Clear();
_owner.RootPanel.Clear();
_owner.ClearWindows();
}