WPF附加属性的类型正在被框架损坏

考虑一些派生类型的标准附属物:

public class DerivedKeyBinding : KeyBinding
{
    public string Name; //shortened, make this propdp
}

public class KeyBindingExtenstions
{
    public static DerivedKeyBinding GetCommand(DependencyObject obj) {
        return (DerivedKeyBinding)obj.GetValue(CommandProperty);
    }

    public static void SetCommand(DependencyObject obj, DerivedKeyBinding value) {
        obj.SetValue(CommandProperty, value);
    }

    public static readonly DependencyProperty CommandProperty =
        DependencyProperty.RegisterAttached("Command", typeof(DerivedKeyBinding), typeof(KeyBindingExtenstions), new UIPropertyMetadata(null, CommandChanged));

    private static void CommandChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) {
        var commandValue = GetCommand(d);
    }
}

稍后在XAML中设置:

<Grid>
    <Grid.Style>
        <Style>
            <Setter Property="local:KeyBindingExtenstions.Command">
                <Setter.Value>
                    <local:DerivedKeyBinding Name="{Binding Title, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type Window}}}"/>
                </Setter.Value>
            </Setter>
        </Style>
    </Grid.Style>
</Grid>

然而,这将在网络上崩溃 var commandValue = GetCommand(d); 由于 local:DerivedKeyBinding KeyBinding 在某个过程中。
出于某种奇怪的原因 DerivedKeyBinding 正在使用类型的值设置类型 键绑定 (尽管价值 明确地 开始 派生键绑定 在XAML中)。

系统InvalidCastException:“无法强制转换”系统类型的对象。窗户。输入键绑定“到类型”AttachedPropertyInStyle。DerivedKeyBinding“

为什么会发生这种情况?我如何解决这个问题?

这个问题似乎与 Name 绑定——如果是静态值,代码将完美地执行。