public MonthlyDataViewer(DataManager dataManager)
        {
            if (dataManager == null)
            {
                throw new ArgumentNullException("data");
            }

            InitializeComponent();

            _dataManager = dataManager;

            // DBから初期設定情報を読み込む。
            _settings = _dataManager.GetMonthlyDataViewerSettings();

            this.RemoveValueChangedEventHandler();

            this.comboBox_Month.SelectedIndex = _settings.month.Month - 1;

            this.chart_Income.Controls.Add(this.label_Income);
            this.label_Income.Top = this.chart_Income.Top + ((this.chart_Income.Height - this.label_Income.Height) / 2) - 45;
            this.label_Income.Left = this.chart_Income.Left + ((this.chart_Income.Width - this.label_Income.Width) / 2) - 23;
            this.chart_Spending.Controls.Add(this.label_Spending);
            this.label_Spending.Top = this.label_Income.Top;

            this.button_PrevMonth.BackColor = CommonConst.PrevNextMonthButtonColor;
            this.button_NextMonth.BackColor = CommonConst.PrevNextMonthButtonColor;
            this.AdjustButtonShape();

            this.numericUpDown_Year.BackColor = CommonConst.MonthControlButtonColor;
            this.comboBox_Month.BackColor = CommonConst.MonthControlButtonColor;
        }