该系统工作流程:超市工作人员在管理商品时，用户对商品的价格，折扣等进行管理，并进行增删改。(1)该管理软件将对商品进行管理和统计,对产品的价格进行录入管理和统计;(2)根据需要对商品名称、价格、是否打折等进行查询，并能显示详细信息；(3)为用户提供账号管理工具，以便用户对账号进行管理，具体为登录修改用户密码；(4)提供商品的增加，删除，修改，对商品进行管理，还可以分类查看打折商品和原价商品。数据库中需要存储的数据:用户登录名、密码、商品名称、价格、是否打折、商品类别、打折价格等。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Data;
using System.Data.SqlClient;


namespace supermarket
{
    public class DBHelper
    {
        private string connString = @“Data Source=（local）;Initial Catalog=SuperMarket;User ID=sa;Password=123456“;
        private SqlConnection connection;

        //连接对象
        public SqlConnection Connection
        {
            get 
            {
                if （connection==null）
                {
                    connection = new SqlConnection（connString）;
                }
                return connection;
            }
        }
        //打开数据连接
        public void OpenConnection（）
        {
            if （Connection.State == ConnectionState.Closed）
            {
                Connection.Open（）;
            }
            else if （Connection.State==ConnectionState.Broken）
            {
                Connection.Close（）;
                Connection.Open（）;
            }
        }

        //关闭数据库
        public void CloseConnection（）
        {
            if （Connection.State ==ConnectionState.Open || Connection.State==ConnectionState.Broken）
            {
                Connection.Close（）;
            }
        }
    }
}

 属性            大小     日期    时间   名称
----------- ---------  ---------- -----  ----

    ..A..H.     64512  2020-12-14 19:39  sm\supermarket\.vs\supermarket\v16\.suo

     文件          0  2020-12-14 18:47  sm\supermarket\.vs\supermarket\v16\Server\sqlite3\db.lock

     文件     577536  2020-12-14 19:17  sm\supermarket\.vs\supermarket\v16\Server\sqlite3\storage.ide

     文件     186880  2020-12-16 21:51  sm\supermarket\supermarket\bin\Debug\supermarket.exe

     文件      83456  2020-12-16 21:51  sm\supermarket\supermarket\bin\Debug\supermarket.pdb

     文件      11600  2020-12-19 12:38  sm\supermarket\supermarket\bin\Debug\supermarket.vshost.exe

     文件        490  2019-03-19 12:46  sm\supermarket\supermarket\bin\Debug\supermarket.vshost.exe.manifest

     文件       1363  2020-12-15 18:02  sm\supermarket\supermarket\DBHelper.cs

     文件        367  2020-12-11 23:26  sm\supermarket\supermarket\frmAbout.cs

     文件       3249  2020-12-11 23:26  sm\supermarket\supermarket\frmAbout.Designer.cs

     文件       5817  2020-12-11 23:26  sm\supermarket\supermarket\frmAbout.resx

     文件       3779  2020-12-15 19:26  sm\supermarket\supermarket\frmChangePwd.cs

     文件       6110  2020-12-11 23:26  sm\supermarket\supermarket\frmChangePwd.Designer.cs

     文件       5817  2020-12-11 23:26  sm\supermarket\supermarket\frmChangePwd.resx

     文件       7882  2020-12-16 19:01  sm\supermarket\supermarket\frmEditCommodity.cs

     文件       9789  2020-12-13 19:04  sm\supermarket\supermarket\frmEditCommodity.Designer.cs

     文件       5817  2020-12-13 19:04  sm\supermarket\supermarket\frmEditCommodity.resx

     文件       3014  2020-12-15 18:36  sm\supermarket\supermarket\frmLogin.cs

     文件       6330  2020-12-11 22:43  sm\supermarket\supermarket\frmLogin.Designer.cs

     文件       5817  2020-12-11 22:43  sm\supermarket\supermarket\frmLogin.resx

     文件       6136  2020-12-15 17:59  sm\supermarket\supermarket\frmSuperMarket.cs

     文件      10107  2020-12-14 19:13  sm\supermarket\supermarket\frmSuperMarket.Designer.cs

     文件       6212  2020-12-14 19:13  sm\supermarket\supermarket\frmSuperMarket.resx

     文件       1454  2020-12-16 19:30  sm\supermarket\supermarket\frmSuperMarketMain.cs

     文件       6759  2020-12-16 19:30  sm\supermarket\supermarket\frmSuperMarketMain.Designer.cs

     文件       6015  2020-12-16 19:30  sm\supermarket\supermarket\frmSuperMarketMain.resx

     文件       5420  2020-12-15 18:00  sm\supermarket\supermarket\obj\x86\Debug\DesignTimeResolveAssemblyReferences.cache

     文件       7135  2020-12-17 23:43  sm\supermarket\supermarket\obj\x86\Debug\DesignTimeResolveAssemblyReferencesInput.cache

     文件       4420  2020-12-19 12:38  sm\supermarket\supermarket\obj\x86\Debug\supermarket.csproj.FileListAbsolute.txt

     文件       1676  2020-12-16 19:30  sm\supermarket\supermarket\obj\x86\Debug\supermarket.csproj.GenerateResource.Cache

............此处省略52个文件信息