void in C# generics?

Question

I have a generic method that takes a request and provides a response.

public Tres DoSomething<Tres, Treq>(Tres response, Treq request)
{/*stuff*/}

But I don't always want a response for my request, and I don't always want to feed request data to get a response. I also don't want to have to copy and paste methods in their entirety to make minor changes. What I want, is to be able to do this:

public Tre DoSomething<Tres>(Tres response)
{
    return DoSomething<Tres, void>(response, null);
}

Is this feasible in some manner? It seems that specifically using void doesn't work, but I'm hoping to find something analogous.

Answer 1

You cannot use void, but you can use object: it is a little inconvenience because your would-be-void functions need to return null, but if it unifies your code, it should be a small price to pay.

This inability to use void as a return type is at least partially responsible for a split between the Func<...> and Action<...> families of generic delegates: had it been possible to return void, all Action<X,Y,Z> would become simply Func<X,Y,Z,void>. Unfortunately, this is not possible.