如何从 Windows 应用商店应用程序的隐藏代码绑定到 C# 中的自定义附加属性？

我有一个我定义的附加属性。

namespace Controls
{
public class StateManager : DependencyObject
{
    public static string GetVisualState(DependencyObject obj)
    {
        return (string)obj.GetValue(VisualStateProperty);
    }

    public static void SetVisualState(DependencyObject obj, string value)
    {
        obj.SetValue(VisualStateProperty, value);
    }

    // Using a DependencyProperty as the backing store for VisualStateProperty.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty VisualStateProperty =
        DependencyProperty.RegisterAttached("VisualState", typeof(string), typeof(StateManager),
        new PropertyMetadata(null,
            (s, e) => {
                var stateName = (string)e.NewValue;
                var ctrl = s as Control;
                if (ctrl == null) throw new InvalidCastException("You can only attach VisualState properties to Controls");

                if (!string.IsNullOrEmpty(stateName))
                    VisualStateManager.GoToState(ctrl, stateName, true);
            }));
}
}

我可以像这样在 XAML 中绑定到此属性：

<controls:TitleStrip
    controls:StateManager.VisualState=
          "{Binding (controls:StateManager.VisualState), ElementName=pageRoot}" 
    Grid.Column="1"/>

现在，我需要在代码后面动态创建到同一属性的绑定，所以我尝试了以下方法：

var pp = new PropertyPath("(controls:StateManager.VisualState)");
var binding = new Binding() { Path= pp, Source=this };
BindingOperations.SetBinding(ct, StateManager.VisualStateProperty, binding);

不幸的是，设置绑定的 Path 属性会引发 ArgumentException，指出：“值不在预期范围内。”

相反，如果我用“(Grid.Row)”替换我的属性，则不会引发异常。

对 Windows 10 的进一步调查表明，如果尝试将附加属性 Controls.StateManager.VisualState 绑定到控件 ct 上同名的附加属性上，这似乎可以在 C# 代码隐藏中工作：

string bindingxaml =
@"<ResourceDictionary
xmlns:controls=""using:Controls""
xmlns=""http://schemas.microsoft.com/winfx/2006/xaml/presentation""
xmlns:x=""http://schemas.microsoft.com/winfx/2006/xaml""
>
<Binding x:Key=""binding"" Path=""(controls:StateManager.VisualState)"" />
</ResourceDictionary>";

ResourceDictionary dict = XamlReader.Load(bindingxaml) as ResourceDictionary;
Binding binding = dict["binding"] as Binding;
binding.Source = this;
BindingOperations.SetBinding(ct, StateManager.VisualStateProperty, binding);

奇怪的是，如果您不将其包含在 ResourceDictionary 中，并尝试将 Binding 对象创建为唯一的子对象，则会引发异常。