never mind. I found it in the documentation. For those interested:
ColorDrawable
A drawable that has a solid color and can have round corners.
Example:
Dim cd As ColorDrawable
cd.Initialze(Colors.Green, 5dip)
Button1.Background = cd
Erel: By the way, the above sample code from the documentation has a spelling error in this line:
cd.Initialze(Colors.Green, 5dip)
where
Initialze should of course be
Initialize