if ((dtpEnd.Value - dtpStart.Value).Days > 14)
                for (DateTime i = dtpStart.Value; i <= dtpEnd.Value; i = i.AddDays((dtpEnd.Value - dtpStart.Value).Days / 14))
                {
                    chPlan.Series[2].Points.AddXY((DateTime)i, 0);
                    chPlan.Series[2].Points[chPlan.Series[2].Points.Count - 1].AxisLabel = i.ToString("dd.MM.yyyy") + " " + Week[(int)i.DayOfWeek];
                }
            else
                for (DateTime i = dtpStart.Value; i <= dtpEnd.Value; i = i.AddDays(1))
                {
                    chPlan.Series[2].Points.AddXY((DateTime)i, 0);
                    chPlan.Series[2].Points[chPlan.Series[2].Points.Count - 1].AxisLabel = i.ToString("dd.MM.yyyy") + " " + Week[(int)i.DayOfWeek];
                }