Question

A long time ago, I saw something that allowed you to chain a series of methods together dynamically. Can’t remember if it was in C#, or C++.

It goes something like this:

Methods:

Foo();
Bar();
Moar();

An object is then created that subscribes (for lack of a better word) to any or all of the methods above (depending on the programmer’s specification), and whatever is passed into this object will run through all the subscribed methods.

I ask, because I am working on a kernel for a program, which depending on a variety of choices, may or may not need certain methods. Since this program needs to be very tightly coded (I prefer not to waste a processor cycle on an if / else statement…it will add up), I was wondering if anyone recalls what I am attempting to convey, and what the C# equivalent would be.

Thanks,
-R

Answer 1

It sounds like an event:

declared:

public event Action Something;

subscribed:

obj.Something += x.Foo;
...
obj.Something += y.Bar;
...
obj.Something += z.Moar;

then invoked:

protected virtual void OnSomething() {
    var handler = Something;
    if(handler != null) handler();
}
...
OnSomething(); // call ^^^^^^

which would invoke all the 3 methods, but with loose coupling.

Note you can do exactly the same just with a delagate rather than an event. Note also that events generally have a more specific void (object sender, SomeEventArgs args) signature (but this is convention, not a requirement).