sorry, I should said it cleary.
my company got one old vfp application which can generate some invoice and export to EXCEL.
syntax :
select invoice,invoicedate,currency,totalamount from myInvoiceTable into Cursor pTemp
SELECT pTemp
EXPORT TO C:\myExcel.xls (the invoice date is string type in excel field)

Now, In vb.net I use excel.application , export the invoice date to myExcel_net.xls(the type become date field)
my client got a marco with some forumla to link with myExcel.xls

However, As I can't convert date field into String type, he complaint that his marco doesn't work anymore.
I am very suffer .....