Accessing combobox item from DataGridView

I have a form with 4 elements:

- A ComboBox listing customers, I populate this combobox on form load with a list of all customers from a database... I have a customerClass class with a overridden ToString() method so that the combobox displays properly (Lastname, Firstname)... and a getID() method to return the ID of the given customer. I can get the ID by doing:

customerClass selectedCustomer = (customerClass)cbCustomer.SelectedItem;
int custID = selectedCustomer.getID();

- Next I have a date picker, which I can access fine.

- I then have a DataGridView control which allows the user to enter items bought by the selected customer. There are 2 columns, the first column is a ComboBox column which lists all the items available (also from a database), and the second column is a simple text entry column for the quantity bought. I populate the combobox column like this:

DataGridViewComboBoxColumn dgvc = (DataGridViewComboBoxColumn)dgvItems.Columns[0];
for each record in item list database {
itemClass newItem = new itemClass(<itemID>, <item name>, <item price>);
dgvc.Items.Add(newItem);
}

This works properly in listing all of my items in the combobox column, however I have no idea how to actually get the selected item and cast it back to my itemClass object, so that I can go about finding the price, item ID, etc.

Any help would be appreciated.