附加属性的change事件中无法访问依赖属性

Question

问题描述： 直接上图

如上图所示，里面涉及三个对象，1附加属性AccessibilityVisibilityAttach，
2.依赖属性SwitchImageVisibility，
3.附加属性AccessibilityVisibilityAttach的onchange事件OnAccessibilityVisibilityAttachChanged

下面附上相应的代码

public static Visibility GetAccessibilityVisibilityAttach(DependencyObject obj)
{
    return (Visibility)obj.GetValue(AccessibilityVisibilityAttachProperty);
}
public static void SetAccessibilityVisibilityAttach(DependencyObject obj, Visibility value)
{
    obj.SetValue(AccessibilityVisibilityAttachProperty, value);
}
public static readonly DependencyProperty AccessibilityVisibilityAttachProperty =
    DependencyProperty.RegisterAttached("AccessibilityVisibilityAttach", typeof(Visibility), typeof(UCAccessibilityFootViewModel), 
        new PropertyMetadata(Visibility.Visible, OnAccessibilityVisibilityAttachChanged));

/// <summary>
/// 是否显示切换图标
/// </summary>
public Visibility SwitchImageVisibility
{
    get { return (Visibility)GetValue(SwitchImageVisibilityProperty); }
    set { SetValue(SwitchImageVisibilityProperty, value); }
}
public static readonly DependencyProperty SwitchImageVisibilityProperty =
    DependencyProperty.Register("SwitchImageVisibility", typeof(Visibility), typeof(UCAccessibilityFootViewModel), new PropertyMetadata(Visibility.Visible));

private static void OnAccessibilityVisibilityAttachChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e)
{
    Visibility newVisibility = (Visibility)e.NewValue;
    SetAccessibilityVisibilityAttach(obj, newVisibility);

    SwitchImageVisibility = newVisibility;   //这里是无法直接访问SwitchImageVisibility的
}

提出问题：
我无法在静态OnAccessibilityVisibilityAttachChanged函数中去访问
非静态的依赖属性SwitchImageVisibility。
在此请教各位，期待大家的指点，感谢！

Answer 1

你输出下 typeof 那个类型，可以考虑反射去访问属性