Access not saved excel file

I want to access the cell values present in an excel file which is not saved.
An already opened excel file having some values.

I wrote below code:

set excl=getobject("","excel.application")
set worksheet1= excl.ActiveSheet
for each cell in worksheet1.usedrange
msgbox cell.value
next

but in 3rd row I am getting error of object required Worksheet1

Kindly help