windows-runtime - 是否可以在 Windows 运行时为 Windows Phone 创建一个未密封的基引用类？

Question

是否可以在 Windows 运行时的 Windows Phone 8 变体中创建一个基类，供其他公共(public)引用类使用？

对于 Windows 应用商店应用 MSDN documents a way to do this (见下文)。

然而，这依赖于将 Windows::UI::Xaml::DependencyObject 作为允许的未密封基类。

由于 Windows Phone 8 没有 C++/XAML 编程功能，因此此类不可用。您不得创建在公共(public) ref 类中可见的顶级对象，因为这会发出编译器警告。

是否有另一个合适的基类可以在 Windows Phone 8 中用来代替 Windows::UI::Xaml::DependencyObject？

namespace InheritanceTest2 
{
    namespace WFM = Windows::Foundation::Metadata;

    // Base class. No public constructor.
    [WFM::WebHostHidden]
    public ref class Base : Windows::UI::Xaml::DependencyObject 
       // DependencyObject NOT AVAILABLE ON WP8!
    {
    internal:
        Base(){}
    protected:
        virtual void DoSomething (){}
        property Windows::UI::Xaml::DependencyProperty^ WidthProperty;
};

// Class intended for use by client code across ABI.
// Declared as sealed with public constructor.
public ref class MyPublicClass sealed : Base
{
public:
    MyPublicClass(){}
    //...
};

Answer 1

http://channel9.msdn.com/Events/Build/2012/3-049

WinRT doesn't really support the notion of inheritance for classes. A special case is made for XAML controls in Windows 8, but we don't support C++ XAML on Windows Phone 8.

Peter Torr (MSFT)