Windows Development

public interface class IA
{
    property int ID { int get(); }
};
ref class A : IA
{
public:
    virtual property int ID { int get() { return 0; } }
};

public interface class IB : IA {};
ref class B : A, IB {};

public ref class Create sealed {
public:
    static IB^ CreateB() { return ref new B(); }
};

Quote:

1>c:\dev\tests\windowsruntimecomponent1\windowsruntimecomponent1\class1.h(16): error C3766: 'WindowsRuntimeComponent1::B' must provide an implementation for the interface method 'int WindowsRuntimeComponent1::IA::ID::get(void)'
1> c:\dev\tests\windowsruntimecomponent1\windowsruntimecomponent1\class1.h(7) : see declaration of 'WindowsRuntimeComponent1::IA::ID::get'
1>c:\dev\tests\windowsruntimecomponent1\windowsruntimecomponent1\class1.h(16): warning C4570: 'WindowsRuntimeComponent1::B' : is not explicitly declared as abstract but has abstract functions
1>c:\dev\tests\windowsruntimecomponent1\windowsruntimecomponent1\class1.h(20): error C2259: 'WindowsRuntimeComponent1::B' : cannot instantiate abstract class

ref class B : A, public IB
{
public:
    virtual property int ID { int get() override { return A::ID; } }
};