Populate a credit card expiration month DropDownList
for (int i = 1; i <= 12; i++)
{
    DateTime month = new DateTime(2011, i, 1);
    ListItem li = new ListItem(month.ToString("MMM (MM)"), month.ToString("MM"));
    ddlExpirationDateMonth.Items.Add(li);
}
ddlExpirationDateMonth.Items[0].Selected = true;

//Populate the credit card expiration year DropDownList (go out 7 years) 
for (int i = 0; i <= 6; i++)
{
    String year = (DateTime.Today.Year + i).ToString();
    ListItem li = new ListItem(year, year);
    ddlExpirationDateYear.Items.Add(li);
}
ddlExpirationDateYear.Items[0].Selected = true;