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。
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。
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 { /// <summary> /// 用户ID /// </summary> public int Id { get; set; } /// <summary> /// 用户名 /// </summary> public string Name { get; set; } /// <summary> /// 密码 /// </summary> 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); /// <summary> /// 从数据库查找用户 /// </summary> /// <param name="_userInfoModel"></param> /// <returns></returns> 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; } /// <summary> /// 从数据库查找用户名 /// </summary> /// <param name="_userInfoModel"></param> /// <returns></returns> 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; } /// <summary> /// 查询所有数据 /// </summary> /// <returns></returns> public List<UserInfoModel> MySqlSelectUserAll() { List<UserInfoModel> list = new List<UserInfoModel>(); 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; } /// <summary> /// 删除用户 /// </summary> /// <param name="_userInfoModel"></param> 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; } /// <summary> /// 插入数据 /// </summary> /// <param name="_userInfoModel"></param> /// <returns></returns> 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; } /// <summary> /// 更新数据 /// </summary> /// <param name="_userInfoModel"></param> /// <returns></returns> 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 { /// <summary> /// 判断用户是否存在 /// </summary> /// <param name="name"></param> /// <param name="pwd"></param> /// <returns></returns> 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; } } /// <summary> /// 判断用户名是否存在 /// </summary> /// <param name="name"></param> /// <returns></returns> 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; } } /// <summary> /// 查看所有的用户 /// </summary> public List<string> CheckAllUser() { List<UserInfoModel> userInfoModel = new List<UserInfoModel>(); List<string> list = new List<string>(); UserInfoDAL userInfoDAL = new UserInfoDAL(); userInfoModel = userInfoDAL.MySqlSelectUserAll(); for (int i = 0; i < userInfoModel.Count; i++) { list.Add(userInfoModel[i].Name); } return list; } /// <summary> /// 删除所选中的用户 /// </summary> 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; } } /// <summary> /// 添加用户 /// </summary> /// <param name="name"></param> /// <param name="pwd"></param> 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); } } /// <summary> /// 更新用户密码 /// </summary> /// <param name="_userInfoModel"></param> /// <returns></returns> 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