private void button2_Click(object sender, EventArgs e)
        {
            DateItem dt = (DateItem)lstResults.SelectedItem;

            txtNextDate.Text = RecurrenceHelper.GetNextDate(dt.Value, txtSeriesInfo.Text).ToString("d MMM, yyyy   ddd");
        }
        private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            DateItem dt = (DateItem)lstResults.SelectedItem;

            monthCalendar1.SetDate(dt.Value);
        }