How to correctly do inheritance with runtimeclass using C++?

[HO-COOH]

If I have a runtimeclass Base (that is I authored myself, not WinUI), and I want my runtimeclass Derived to inheirt Base, what's the real correctly way to achieve that?

//Base.idl
    [bindable]
    [default_interface]
    unsealed runtimeclass Base : Microsoft.UI.Xaml.DependencyObject
    {
        Base();
    }

//Derived.idl
    [bindable]
    [default_interface]
    runtimeclass Derived : Base
    {
        Derived();
        Int32 MyProperty;
    }

Without changing anything in code-behind, I got compile error.

[HO-COOH]

Just post my answer here in case any one needed:

• Include the implementation header in this derived runtimeclass's implementation header
• In the implementation class's implementation header, add your base class in the DerivedT<...> argument list

#include "Base.h"
#include "Derived.g.h"
winrt::...::implementation
{
    struct Derived : Derived<Derived, Base> {...};
}