How to iterate over columns in a range

I would like to do something like this: I want to iterate over the selected rows in the active worksheet and for each row, iterate or access the cells in that row.

Dim myRange As Range
Dim wksSheet As Worksheet
Dim A$

Set myRange = Selection
For Each r In myRange
A$ = ""

A$ = ActiveSheet.Cells(r, 1) <---DOES NOT WORK
A$ = A$ + ", " + ActiveSheet.Cells(r, 2)
A$ = A$ + ", " + ActiveSheet.Cells(r, 3)
MsgBox A$
Next r
End Sub

Thanks.

RON