public void Refresh(string from, string to, DateTime minDate, DateTime maxDate)
        {
            minDate = minDate.Date;
            maxDate = maxDate.Date;
            SuspendLayout();
            Controls.Clear();

            var curDate = minDate;

            while (curDate <= maxDate)
            {
                var opened = QueryParam.DepartureDate == curDate || QueryParam.AlternativeDate.Contains(curDate);
                var btn    = new Button()
                {
                    Enabled   = !opened,
                    Text      = curDate.ToString("MM-dd"),
                    FlatStyle = FlatStyle.Flat,
                    BackColor = opened ? Color.FromArgb(174, 209, 163) : Color.FromArgb(163, 179, 209),
                    Size      = new Size(100, 28),
                    Tag       = curDate
                };
                btn.Click += (s, e) =>
                {
                    QueryParam.AddAlternativeDate((DateTime)(s as Button).Tag);
                    ((Button)s).Enabled   = false;
                    ((Button)s).BackColor = Color.FromArgb(174, 209, 163);
                };
                Controls.Add(btn);

                curDate = curDate.AddDays(1);
            }
            ResumeLayout();
        }