Question

I wanted to elaborate on the current project i’m working on but that would be kind long. Instead I’ll just post a programming riddle which basically explains what i’m trying to accomplish. 🙂

abstract class A
{
    // key = Derived Class name, value = list of properties the derive class exposes.
    private static Dictionary<string, List<string>> _DerivedPropertyNames;

    static A()
    {
        InitializeDerivedPropertyNames();
    }

    private static void InitializeDerivedPropertyNames()
    {
        //...???...
    }
}

The riddle is how can you create an abstract base class which will hold a static cache of all its derived classes properties?

Note that the idea is to avoid loading an assembly by name.

Answer 1

If you can wait for instances of the child types to be instantiated, then you could use A’s regular constructor to register the implementing class:

public A()
{
    Type childType = GetType();
    string className = childType.Name;
    if (!_DerivedPropertyNames.ContainsKey(className)) {
         // add properties for this class
    }
}

It will be very difficult for you to get the job done in the static constructor, before any instantiation, without adding logic in the child classes (which I suppose you don’t want). The reason is that you won’t be able to enforce all assemblies containing types that implement A to be loaded when A’s static constructor is called.