GridView Footer模板列中给Dropdownlist赋值

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
    string FstWeekEnd,FstWeekEndday;

if (e.Row.RowType == DataControlRowType.Footer)
    {
        DropDownList ddl = (DropDownList)e.Row.FindControl("new_date");
        for (int i = 0; i < 7; i++)
        {
            FstWeekEnd = DateTime.Now.AddDays(Convert.ToDouble((1 - Convert.ToInt16(DateTime.Now.DayOfWeek))) + 14 + i).ToString("yyyy-MM-dd");

FstWeekEndday = DateTime.Now.AddDays(Convert.ToDouble((1 - Convert.ToInt16(DateTime.Now.DayOfWeek))) + 14 + i).ToString("MM-dd");

ddl.Items.Add(new ListItem(FstWeekEndday, FstWeekEnd));

}
    }
}