Visual Basic: Bounding Box of current part

Hello

I found this Journal which returns the bouding box (dimensions) of a part you can select. I tried to modify it so it doesn't need the selecting anymore, but wasn't successful. How can I do this for the current work part?

It doesn't have to work for assemblys.

Edit: I don't need the directions, just the dimensions of the part as information for shipping. For Example: 150x20x5.

Thank you and Regards