//确定按钮
private void btnOk_Click(object sender, EventArgs e)
{
double totalPrices = 0d;
//传进下拉选择值和原价，计算实际收费结果
totalPrices = cf.GetFactTotal(cbxType.SelectedItem.ToString(), Convert.ToDouble(txtPrice.Text) * Convert.ToDouble(txtNum.Text));
total = total + totalPrices;
lbxList.Items.Add("单价：" + txtPrice.Text + " 数量：" + txtNum.Text + " " + cbxType.SelectedItem + " 合计： " + totalPrices.ToString());
lblResult.Text = total.ToString();
}
