设计模式-策略模式

一 没用模式前

 

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace Demo
{
    public partial class main : Form
    {
        public main()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            try
            {
                double price = Convert.ToDouble(textBox1.Text);
                double num = Convert.ToInt32(textBox2.Text);
                string content = comboBox1.SelectedValue.ToString();
                listBox1.Items.Add("商品：" + "" + " 单价：" + price + " 数量：" + num + " 合计：" + sum(price, num, content) + " 打折情况：" + content);
                double m = 0;
                for (int i = 0; i < listBox1.Items.Count; i++)
                {
                    m += Convert.ToDouble(sum(price, num, content));
                }
                label4.Text = "RMB " + Convert.ToString(m) + "元";
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message.ToString());
            }
        }
        public double sum(double price, double num, string content)
        {
            Strategy.BaseInterface IFBase;
            double allPrice = price * num;
            switch (content)
            {
                case "全价":
                    return allPrice;
                    break;
                case "八折":
                    return allPrice * 0.8;
                    break;
                case "六折":
                    return allPrice * 0.6;
                    break;
                case "买一送一":
                    return allPrice;
                    break;
                case "满二百减一百":
                    if (allPrice >= 200)
                    {
                        int div = Convert.ToInt32(allPrice / 200);
                        return allPrice - div * 100;
                    }
                    else
                    {
                        return allPrice;
                    }
                    break;
                default :
                    return 0;
                    break;
            }
        }
        private void button2_Click(object sender, EventArgs e)
        {
            textBox1.Text = "";
            textBox2.Text = "";
            listBox1.Items.Clear();
            label4.Text = "";
        }



        private void Form1_Load(object sender, EventArgs e)
        {
            SqlDataBase.DB db = new SqlDataBase.DB();
            comboBox1.DataSource = db.ComBind();
        }

        private void button3_Click(object sender, EventArgs e)
        {
            
        }
    }
}

 利用模式