hi,

try with the real name of the sheet,
and make sure there is a validation list in cell B11
what is the MsgBox result on the next command line?

MsgBox Sheets("Sheet1").Range("B11").Validation.Formula1

isabelle

Le 2013-08-15 11:16, a écrit :

Hi Isabelle,

Thanks very much for your help again. As I replied to your another post. It seems that dropdown list in my excel file was not named. I ran the code.

string s = oSheet.Range["B11"].Validation.Formula1;

and received the error of "Exception from HRESULT: 0x800A03EC". It means that Formula was not found.