小菜编程成长记（十二 有了门面，程序员的程序会更加体面！）

Code
using System;
using System.Collections.Generic;
using System.Text;
using System.Data;

namespace 商场管理软件.DAL
{
    public class CashAcceptType
    {
        public DataSet GetCashAcceptType()
        {
            //读配置文件到DataSet
            DataSet ds = new DataSet();
            ds.ReadXml("CashAcceptType.xml");
            return ds;
        }
    }
}

Code
namespace 商场管理软件.BLL
{
    public class CashFacade
    {
        const string ASSEMBLY_NAME = "商场管理软件.BLL";
        
        //得到现金收取类型列表，返回字符串数组
        public string[] GetCashAcceptTypeList()
        {
            CashAcceptType cat = new CashAcceptType();
            DataSet ds = cat.GetCashAcceptType();
            int rowCount = ds.Tables[0].DefaultView.Count;
            string[] arrarResult = new string[rowCount];

            for (int i = 0; i < rowCount; i++)
            {
                arrarResult[i] = (string)ds.Tables[0].DefaultView[i]["name"];
            }
            return arrarResult;
        }

        /**//// <summary>
        /// 用于根据商品活动的不同和原价格，计算此商品的实际收费
        /// </summary>
        /// <param name="selectValue">下拉列表选择的折价类型</param>
        /// <param name="startTotal">原价</param>
        /// <returns>实际价格</returns>
        public double GetFactTotal(string selectValue, double startTotal)
        {
            CashAcceptType cat = new CashAcceptType();
            DataSet ds = cat.GetCashAcceptType();

            CashContext cc = new CashContext();
            DataRow dr = ((DataRow[])ds.Tables[0].Select("name='" + selectValue + "'"))[0];
            object[] args = null;
            if (dr["para"].ToString() != "")
                args = dr["para"].ToString().Split(',');

            cc.setBehavior((CashSuper)Assembly.Load(ASSEMBLY_NAME).CreateInstance(ASSEMBLY_NAME + "." 
                                                           + dr["class"].ToString(), false, BindingFlags.Default, null, args, null, null));
            return cc.GetResult(startTotal);

        }
    }
}

Code
double total = 0.0d;//用于总计
CashFacade cf = new CashFacade();
    
private void Form1_Load(object sender, EventArgs e)
{
    //读数据绑定下拉列表
    cbxType.DataSource=cf.GetCashAcceptTypeList();
    
    cbxType.SelectedIndex = 0;
}

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();
}