private void backgroundWorker_DoWork(object sender, DoWorkEventArgs e)
        {
            statisticTypeEnum type = (statisticTypeEnum)this.comboBox1.SelectedValue;

            this.label_title.Text = string.Format("统计方式:{0,-12}统计时间:{1}至{2}",
                                                  this.comboBox1.Text, this.dateTimePicker3.Value.ToShortDateString(), this.dateTimePicker4.Value.ToShortDateString());
            switch (type)
            {
            case statisticTypeEnum.product:
                statisticProduct();
                break;

            case statisticTypeEnum.customer:
                statisticCustomer();
                break;

            case statisticTypeEnum.month:
                statisticMonth();
                break;

            default:
                break;
            }
        }
        private void backgroundWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            statisticTypeEnum type = (statisticTypeEnum)this.comboBox1.SelectedValue;

            switch (type)
            {
            case statisticTypeEnum.product:
                initProductItems();
                break;

            case statisticTypeEnum.customer:
                initCustomerItems();
                break;

            case statisticTypeEnum.month:
                initMonthItems();
                break;

            default:
                break;
            }
            this.invokeEndLoadNotify();
            this.label_notice.Visible = false;
        }