Question

I have the following classes:

 Class A {}

 Class B: A {}

 Class C: A {}

Now, I have 2 functions that fill either B or C with data. At the moment, 2 functions are required because one creates New B() and the other New C().

I would like just one function that I can tell to use either B or C. I cannot just send a class and tell it to be filled, the called function needs to be able to create the classes on the fly.

Answer 1

You can write a generic function with a new constraint on the type argument:

class FillerOfBsAndCs {
    A Fill<T>() where T : new(), A {
        // do the preparations...
        T res = new T();
        // fill res with data
        return res;
    }
}

You can now call this method like this:

FillerOfBsAndCs filler = new FillerOfBsAndCs();
A a1 = filler.Fill<B>();
A a2 = filler.Fill<C>();