Casting from Base To Derived?

Question

Is it possible to cast an object from a base to a derived one? For instance, let's say I have one base object: Animal. From this I have derived a couple of other classes: Cat, Dog. Now I need an Animal but the type at this moment doesn't really matter. So,

Animal blankCanvas = new Animal();

Along the way I changed my mind and now want to change that Animal to a Dog. However, I don't understand how I would go about doing that. I know the business rules to convert from an Animal to a Dog but I just don't know how to implement that.

Answer 1

Yes, you can cast a base reference to a derived reference.

But you seem to want to convert an instance. That is not casting and it is not directly possible.

Your logic should be such that you know what type you want at the point when you create it.

The following could make sense:

Animal blankCanvas = null;
...
blankCanvas = new Dog();

To help you to keep the correct path, define Animal as an abstract class
After all, what does an instance of Animal represent?