private void FormSaleView_Load(object sender, EventArgs e)
        {
            dateTimePicker2.Value = DateTime.Now;
            dateTimePicker1.Value = dateTimePicker2.Value;
            DataTable dt = db.GetSalesReceipt();

            dataGridView1.DataSource = dt;
            dataGridView1.ClearSelection();
            if (parentflag == 1)
            {
                comboBox2.SelectedItem = "未结算";
                GridViewTypeScreen(0);//筛选未结算
                comboBox2.Enabled = false;
            }
            else
            {
                comboBox2.SelectedItem = "全部";
            }
        }