string a = DateTime.Now.ToShortDateString();
        string b = DateTime.Now.Add(TimeSpan.FromDays(1)).ToShortDateString();
        DateTime c =DateTime.Now.Subtract(TimeSpan.FromDays(-16)); 
        ArrayList arrlist = new ArrayList();
        arrlist.Add(a);
        arrlist.Add(b);
        arrlist.Add(c);
        if (arrlist.Count > 0)
        {
            for (int i = 0; i < arrlist.Count; i++)
            {
                Calendar1.SelectedDates.Add(Convert.ToDateTime(arrlist[i]));
                 
            }
        }