System.Windows.Freezable 在未被引用的程序集中定義
報錯信息如下：
解決方法 添加windowsbase.dll 引用
Freezable 類別
Defines an object that has a modifiable and a read-only (frozen) state. Classes that derive from Freezable provide detailed change notification, can be made immutable, and can clone themselves.
命名空間: System.Windows
組件： WindowsBase (在 windowsbase.dll 中)
XML 命名空間： http://schemas.microsoft.com/winfx/2006/xaml/presentation