private void button2_Click(object sender, EventArgs e)
        {
            var t = new TextboxInput();

            t.ShowDialog();
            try
            {
                License.ClientNumber = long.Parse(t.Result);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString());
            }
        }
        private void button_SetDays_Click(object sender, EventArgs e)
        {
            var t = new TextboxInput();

            t.ShowDialog();
            try
            {
                License.DaysAllowed = int.Parse(t.Result);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString());
            }
        }