程序代码：

using System;
using System.Collections.Generic;
using using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using namespace 价格计算
{
    public partial class 盈亏计算 : Form
    {
        public 盈亏计算()
        {
            InitializeComponent();
        }
        private void yj_TextChanged(object sender, EventArgs e)
        {
            try
            {
                double y = 0.996 * Convert.ToDouble(xj.Text) - 1.004 * Convert.ToDouble(yj.Text);
                double zdgj = 1.008 * Convert.ToDouble(yj.Text) + 0.002;
                zd.Text = Convert.ToString(zdgj);
                if (y > 0.002)
                {
                    yl.Text = "是";
                }
                else yl.Text = "否";
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
        private void xj_TextChanged(object sender, EventArgs e)
        {
            try
            {
                double y = 0.996 * Convert.ToDouble(xj.Text) - 1.004 * Convert.ToDouble(yj.Text);
                if (y > 0.002)
                {
                    yl.Text = "是";
                }
                else yl.Text = "否";
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
        private void yl_Click(object sender, EventArgs e)
        {
            try
            {
                double y = 0.996 * Convert.ToDouble(xj.Text) - 1.004 * Convert.ToDouble(yj.Text);
                if (y > 0.002)
                {
                    yl.Text = "是";
                }
                else yl.Text = "否";
            }
            catch (Exception)
            {
            }
          
        }
        private void 盈亏计算_Load(object sender, EventArgs e)
        {
            xj.Text = "0";
            yj.Text = "0";
        }

    }
}