c winform mysql类_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。
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
{
///
/// 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