How to validate a DataGridViewComboBoxCell??

Question

I have problem with validating combo box cells. I can't  figure it out how to do it. CellValidating event gives me only the formatted value of the cell. Thtat's useless for combo boxes. I need to validate the value not the displayed text. The value object of the combo box cell is null during the (first) Validation event. It gets updated after the validation. So how to validate the actual value of a combo box cell?

Thanks!