Question

I have a List which must contain IInteract Objects. But IInteract is a generic interface which requires 2 type arguments.

My main idea is iterate through a list of Objects and “Interact” one with another if they didn’t interact yet.
So i have this object

List<IObject> WorldObjects = new List<IObject>();

and this one:

private List<IInteract> = new List<IInteract>();

Except I can’t compile the last line because IInteract requires 2 type arguments. But I don’t know what the arguments are until I add them. I could add interactions between Objects of Type A and A… or Objects of Type B and C.

I want to create “Interaction” classes which do something with the “acting” object and the “target” object, but I want them to be independent from the objects… so I could add an Interaction between for instance… “SuperUltraClass” and… an “integer”.

Am I using the wrong approach?

Answer 1

Assuming IInteract is defined as something like

interface IInteract<T1, T2>

and you are using it for a field of a class Foo:

class Foo
{
  List<IInteract...> field;
}

Then if you want to defer the decision of what types to bind to the IInteract type arguements you need to parameterize the container class:

class Foo<T1, T2>
{
   List<IInteract<T1, T2>> field;
}

The type arguments to IInteract here will be bound when you define a concrete instantiation of the container class, like: var x = new Foo<int, double>(). This will cause the IInteract field to be of type IInteract<int, double> for that particular instantiation of the Foo generic type.