Inclass conversion from base class to derived class

[brboLikus]

Hello everybody!

My problem is somewhat strange since I can't think of any normal situation where one would like to do what I need, but here it goes. I need to somehow cast a base class to a derived class, but from the base-class code. I would need to do something like this:

class Base
{
    public Base() { }
    public void Convert()
    {
        this = new Derived(); 
        // this, of course, doesn't work
    }
}
class Derived : Base
{
    public Derived() { }
}

Now, the reason I need to do this is because I need to serialize a list that contains the Base class type objects, but I don't know what do the derived classes look like. All I know is that they have a parameter-less constructor, their full names and the DLL they are in. This gives me the possibility to use the Activator function and fill my list up. But I cannot write the functions for the base class that the IXmlSerializabl e interface demands because to do so I must initialize the base class as a derived class of a specific type, but within the base class itself. I do know that I can use wrappers for the data, and then fill the list using the Activator class, but since I use the base class extensively throughout my project, it would be a tough thing to do..

So, any suggestions are more than welcome.