protected void Check(object sender, EventArgs e) { time.Items.Clear(); string date = Calendar1.SelectedDate.ToShortDateString(); string mySQLDate = date.Split('.')[2] + '-' + date.Split('.')[1] + '-' + date.Split('.')[0]; Debug.WriteLine(mySQLDate); List <string> items = MySQLServer.get_times(mySQLDate); bool[] used = new bool[12]; foreach (string item in items) { int begin = int.Parse(item.Split(':')[0]); for (int hour = begin - 1; hour < begin + 2; ++hour) { if (hour - 10 >= 0) { used[hour - 10] = true; } } } for (int hour = 10; hour < 22; ++hour) { if (!used[hour - 10]) { string h = hour.ToString() + ":00:00"; time.Items.Add(new ListItem(h)); } } }