Move drawing objects from one layer to another

As my subject says, I'm looking for a way via the API to move drawing objects from one layer to another; we have a large number of drawings with various annotations and such on incorrect layers, and I'm looking for a way to easily move them. I started off thinking I would just make a selection via 'SketchBoxSelect' or 'SelectByID', but then I just have a list of objects of unknown type, and thus no way to access the 'layer' property.

Wondering if anyone has code already for something like that, or pointers on where to start.

In case it makes a difference, I'm doing this in C#

Thanks

SolidworksApi macros