winform+mysql入门学习

  毕业后,第一份工作是写单片机(C)代码的,这一份也是写C代码的(emmmmmmmmm,虽然入职两个多月了一行代码也没写过啊哈哈哈哈),所以好久没写过博客了,周末没事干(没有女朋友,单身23年呜呜呜呜呜)就学了下C#和MySQL,然后就写了个最简单的类似于“hello world”的小项目-图书管理系统,这部分博文只有用户管理部分的,这篇文章主要是记录自己的学习过程。

winform+mysql入门学习_第1张图片

  C#没什么好说的,只不过是一种面向对象编程语言,大学期间上课不认真听讲学习的,啊哈哈哈哈,MySQL是在bilibili看某智博客的视频学的,都算是半路出家的,所以博文水平低,质量差大佬勿喷,当然这也是我自己学习的记录,大佬可以细心指教,千恩万谢。

  首先说下C#的三层架构,如下这段话是从大佬的博客里面学习的:

  三层架构分为:表现层(UI(User Interface))、业务逻辑层(BLL(Business Logic Layer))、数据访问层(DAL(Data Access Layer))再加上实体类库(Model)。实体类库(Model),主要存放数据库中的表字段;数据访问层(DAL),主要是存放对数据类的访问,即对数据库的添加、删除、修改、更新等基本操作;业务逻辑层(BLL)对传送数据进行逻辑判断分折,并进行传送正确的值;表现层(UI)即用户界面层。

         如下图所示,是我的工程文件结构,2_StudentForm是表示(UI)层,添加的是Windows窗体应用程序;StudentBLL是业务逻辑层,StudentDAL是数据访问层,StudentModel是实体类库,这三个均是类库。

winform+mysql入门学习_第2张图片

 UI层没什么好说的,我这种菜鸟还是喜欢拖控件,然后写需要的事件就行。

  Model层与数据库字段表相对应,如下:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
 
namespace StudentModel
{
    public class UserInfoModel
    {
        /// 
        /// 用户ID
        /// 
        public int Id { get; set; }
 
        /// 
        /// 用户名
        /// 
        public string Name { get; set; }
 
        /// 
        /// 密码
        /// 
        public string Pwd { get; set; }
    }
}

 DAL是数据库操作的相关代码,在DAL类库中引用Model类库,我就写了最基础的sql操作代码,如下:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using StudentModel;
using MySql.Data.MySqlClient;
using System.Data;
 
namespace StudentDAL
{
    public class UserInfoDAL
    {
        const string str = "server = localhost;user = root;password=1234;database = student";
        MySqlConnection conn = new MySqlConnection(str);
 
        /// 
        /// 从数据库查找用户
        /// 
        /// 
        /// 
        public UserInfoModel MySqlSelectUser(UserInfoModel _userInfoModel)
        {  
            conn.Open();
            string sqlstr = String.Format("select * from userinfo where name = '{0}' and pwd = '{1}'", _userInfoModel.Name, _userInfoModel.Pwd);
            MySqlCommand cmd = new MySqlCommand(sqlstr, conn);
            MySqlDataReader reader = cmd.ExecuteReader();
            UserInfoModel user = new UserInfoModel();
 
            if(reader.Read())
            {
               user.Id = reader.GetInt32(0);
               user.Name = reader.GetString(1);
               user.Pwd = reader.GetString(2);
            }
 
            conn.Close();
            return user;
        }
 
        /// 
        /// 从数据库查找用户名
        /// 
        /// 
        /// 
        public UserInfoModel MySqlSelectName(UserInfoModel _userInfoModel)
        {
            conn.Open();
            string sqlstr = String.Format("select * from userinfo where name = '{0}'", _userInfoModel.Name);
            MySqlCommand cmd = new MySqlCommand(sqlstr, conn);
            MySqlDataReader reader = cmd.ExecuteReader();
            UserInfoModel user = new UserInfoModel();
 
            if (reader.Read())
            {
                user.Id = reader.GetInt32(0);
                user.Name = reader.GetString(1);
                user.Pwd = reader.GetString(2);
            }
 
            conn.Close();
            return user;
        }
 
        /// 
        /// 查询所有数据
        /// 
        /// 
        public List MySqlSelectUserAll()
        {
            List list = new List();
            conn.Open();
            string sqlstr = "select * from userinfo";
            DataTable dt = new DataTable();
            MySqlDataAdapter rd = new MySqlDataAdapter(sqlstr, conn);
            rd.Fill(dt);
 
            foreach (DataRow dr in dt.Rows)
            {
                UserInfoModel ai = new UserInfoModel
                {
                    Id = Convert.ToInt32(dr["Id"]),
                    Name = dr["Name"].ToString(),
                    Pwd = dr["Pwd"].ToString()
                };
                list.Add(ai);
            }
 
            conn.Close();
            return list;
        }
 
        /// 
        /// 删除用户
        /// 
        /// 
        public int MySqlDelUser(UserInfoModel _userInfoModel)
        {
            conn.Open();
            string sqlstr = String.Format("delete from userinfo where name = '{0}'", _userInfoModel.Name);
            MySqlCommand cmd = new MySqlCommand(sqlstr, conn);
            int iRet = cmd.ExecuteNonQuery();
            conn.Close();
            return iRet;
        }
 
        /// 
        /// 插入数据
        /// 
        /// 
        /// 
        public int MySqlInsertUser(UserInfoModel _userInfoModel)
        {
            conn.Open();
            string sqlstr = String.Format("insert into userinfo (name,pwd) values('{0}','{1}')",_userInfoModel.Name,_userInfoModel.Pwd);
            MySqlCommand cmd = new MySqlCommand(sqlstr, conn);
            int iRet = cmd.ExecuteNonQuery();
            conn.Close();
            return iRet;
        }
 
        /// 
        /// 更新数据
        /// 
        /// 
        /// 
        public int MySqlUpdateUserPwd(UserInfoModel _userInfoModel)
        {
            conn.Open();
            string sqlstr = String.Format("update userinfo set Pwd = '{0}' where name = '{1}'",_userInfoModel.Pwd,_userInfoModel.Name);
            MySqlCommand cmd = new MySqlCommand(sqlstr, conn);
            int iRet = cmd.ExecuteNonQuery();
            conn.Close();
            return iRet;
        }
    }
}

BLL是界面操作所做的相关处理,在BLL类库中引用DAL和Model类库,如下:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using StudentDAL;
using StudentModel;
 
namespace StudentBLL
{
    public class UserInfoBLL
    {
         
        /// 
        /// 判断用户是否存在
        /// 
        /// 
        /// 
        /// 
        public bool CheckUserExist(string name,string pwd)
        {
            UserInfoModel user = new UserInfoModel();
            user.Name = name;
            user.Pwd  = pwd;
            UserInfoDAL userInfoDAL = new UserInfoDAL();
            UserInfoModel userInfoModel = userInfoDAL.MySqlSelectUser(user);
 
            if (userInfoModel.Name == name && userInfoModel.Pwd == pwd)
            { 
                return true;
            }
            else
            {
                return false;
            }
        }
 
        /// 
        /// 判断用户名是否存在
        /// 
        /// 
        /// 
        public bool CheckUserName(string name)
        {
            UserInfoModel user = new UserInfoModel();
            user.Name = name;
            UserInfoDAL userInfoDAL = new UserInfoDAL();
            UserInfoModel userInfoModel = userInfoDAL.MySqlSelectName(user);
 
            if (userInfoModel.Name == name)
            {
                return true;
            }
            else
            {
                return false;
            }
        }
 
        /// 
        /// 查看所有的用户
        /// 
        public List CheckAllUser()
        {
            List userInfoModel = new List();
            List list = new List();
            UserInfoDAL userInfoDAL = new UserInfoDAL();
            userInfoModel = userInfoDAL.MySqlSelectUserAll();
 
            for (int i = 0; i < userInfoModel.Count; i++)
            {
                list.Add(userInfoModel[i].Name);
            }
 
            return list;
        }
 
        /// 
        /// 删除所选中的用户
        /// 
        public bool DelSelUser(string selname)
        {
            UserInfoModel userinfomodel = new UserInfoModel();
            UserInfoDAL userinfodal = new UserInfoDAL();
            userinfomodel.Name = selname;
            if (userinfodal.MySqlDelUser(userinfomodel) > 0)
            {
                return true;
            }
            else
            {
                return false;
            }
        }
 
        /// 
        /// 添加用户
        /// 
        /// 
        /// 
        public int InsertUser(string name, string pwd)
        {
            UserInfoModel userinfomodel = new UserInfoModel();
            UserInfoDAL userinfodal = new UserInfoDAL();
 
            userinfomodel.Name = name;
            userinfomodel.Pwd = pwd;
 
            if (CheckUserName(name) == true)
            {
                return -1;
            }
            else
            {
                return userinfodal.MySqlInsertUser(userinfomodel);
            }
        }
 
        /// 
        /// 更新用户密码
        /// 
        /// 
        /// 
        public bool UpdateUserPwd(string name,string pwd)
        {
            UserInfoModel userinfomodel = new UserInfoModel();
            UserInfoDAL userinfodal = new UserInfoDAL();
 
            userinfomodel.Name = name;
            userinfomodel.Pwd = pwd;
 
            if (userinfodal.MySqlUpdateUserPwd(userinfomodel) > 0)
            {
                return true;
            }
            else
            {
                return false;
            }
 
        }
    }
}

代码已上传至CSDN,链接如下:

https://download.csdn.net/download/qq_28091109/11292751

 我是半路出家的外行,这也只是我个人学习记录,大佬勿喷

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