Formatting date in vb.net when the date comes from Excel 2003

I'm trying to parse a date to the format 'yyyymmdd'. The date comes from an excel cell that is formated for dates like mm/dd/yyyy.

I read the cell into an arraylist and try to format it something like this

Dim a as new arraylist

Dim xl as excel.application

xl.workbooks.open ...

Dim s as string

Dim i as integer = 0

s = Ctype(xl.cells(r,c).value,string)

a.add(s)

Dim d as new datetime

d = a(i)

Dim ds as string

ds = d.tostring("yyyymmdd")

if I read 10/22/2006 from the spreadsheet, the value d will contain the value #10/22/2006#, but ds will contain 20060022

if I replace d=a(i) with d=ctype(s,datetime), I get the same result. VB's format function does the same thing.

Any suggestions