Question

If I am passed an instance of a class which implements an interface, I do not necessarily know the exact type. If I want to create an array of this class (whatever it may be), I can do so like this:

IWhatever[] ArrayOfClass = (IWhatever[])Array.CreateInstance(InstanceOfClass.GetType(), length);

As long as InstanceOfClass is an instance of a class which implements IWhatever, this works.

The problem is that I can’t seem to figure out how to initialise the members of the array. I thought new IWhatever() might work, but it doesn’t.

How do I construct the members of array?

Answer 1

You’d need to initialize each member to an instance of some class which implements the interface.

If you wanted the same type as InstanceOfClass, and if that type has a default constructor, you could use something like:

for(int i=0;i<ArrayOfClass.Length;++i)
{
    ArrayOfClass[i] = (IWhatever)Activator.CreateInstance(InstanceOfClass.GetType());
}