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What is the seventh floor?
The seven layers as I understand it: It is to add the appearance layer, the factory layer and the interface layer to the seven layers on the basis of the three layers. Doing so can better decouple the code.
Below is a seven-layer picture I drew: it
can help us understand the relationship between the seven layers.
U layer : reference the appearance layer, instantiate the appearance layer, and receive the information returned by the B layer.
Refer to the entity layer and instantiate the entity layer to receive information.
The configuration file also needs to be written in the App.config file of the U layer.
Events of Winform form controls
Facade : Reference to the physical layer.
Reference to layer B, instantiate layer B objects
B layer : refer to the entity layer, receive the value returned by the D layer,
refer to the IDAL interface layer, call the factory method to create the interface,
refer to the Factory factory layer, and instantiate the factory
IDAL interface layer : refer to the entity layer, in order to find the data table
Factory factory layer : To refer to the D layer, the class name of the D layer needs to be used. The
IDAL interface layer is referenced, and reflection is applied.
Refer to the configuration file. When referencing the configuration file, you must refer to the assembly and receive the configuration file.
D layer : reference interface layer: methods to implement the interface
reference entity layer: return database data
SqlHelper is also in the D layer, query and return to the query table
Seven-layer code
Entity layer
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace Entity
{
public class UserInfo
{
public int UserId {
get; set; }
public string UserName {
get; set; }
public string PassWord {
get; set; }
}
}
U layers
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace LoginUI
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
Entity.UserInfo entity = new Entity.UserInfo();
//实例化实体层，用来接收信息
entity.UserName = txtUserName.Text.Trim();
entity.PassWord = txtPassword.Text;
LoginFacade.Facade facade = new LoginFacade.Facade();
//实例化外观层，接受B层返回来的信息
bool flag = new bool();
flag = facade.SelectUser(entity);
{
if (flag != false)
{
if (true)
{
this.Hide();
MessageBox.Show("登录成功！");
}
}
else
{
MessageBox.Show("用户名或密码输入错误，请重新输入！");
txtPassword.Clear();
txtUserName.Clear();//清空
txtUserName.Focus();//光标定位
}
}
}
}
}
Configuration file
<appSettings >
<add key="ConnStr" value ="Server=LAPTOP-4EF4CAKC;Database=Login;User ID=sa;Password=123"/>
<!-- Server=Login，Database=Users -->
<add key="DB" value ="DAL"/>
</appSettings>
Facade层
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace LoginFacade
{
public class Facade
{
public Boolean SelectUser (Entity .UserInfo enuser)
{
bool flag;
LoginBLL.BLL bll = new LoginBLL.BLL();//实例化B层对象
flag = bll.UserBLL(enuser);
return flag;
}
}
}
B layer
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Data;//新添加
using System.Xml;
using LoginFactory;
using IDAL;
namespace LoginBLL
{
public class BLL
{
public bool UserBLL(Entity.UserInfo userInfo)
{
LoginFactory.Factory factory = new LoginFactory.Factory();
//实例化一个工厂
IDAL.LoginIDAL idal = factory.CreatUser();
//调用工厂方法创建接口
DataTable table = idal.GetUsername(userInfo);
//接受D层返回的值
bool flag = new bool();
if (table.Rows.Count == 0)
//返回的是data的类型。如果行数为0，说明没有该账号
{
flag = false;
}
else
{
flag = true;
}
return flag;
}
}
}
IDAL layers
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Data;//新添加的，表示对ADO.NET结构类的访问，可以生成多个管理数据源的数据组件
namespace IDAL
{
public interface LoginIDAL //接口名
{
DataTable GetUsername(Entity.UserInfo userInfo);
//内存数据中的一个表，为了实现“查”？用户名？
}
}
Factory layer
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Reflection;//反射
using System.Configuration;//配置文件
using System.Security.Cryptography.X509Certificates;
using System.Data.SqlTypes;
namespace LoginFactory
{
public class Factory
{
string strDB = ConfigurationManager.AppSettings ["DB"];
//接受配置文件
public IDAL .LoginIDAL CreatUser()
{
string ClassName = strDB + "." + "LoginDAL";//D层的类名
return (IDAL.LoginIDAL)Assembly.Load(strDB).CreateInstance(ClassName);
//反射的应用
}
}
}
DAL layer
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Data.SqlClient;//数据库？
using System.Data;//表示对ADO.NET结构类的访问
using System.Configuration;//配置文件
using System.Data.SqlTypes;
using Entity;
namespace DAL
{
public class LoginDAL:IDAL.LoginIDAL//实现接口的方法 命名空间.类名
{
public DataTable GetUsername(Entity .UserInfo userInfo)
//继承接口层就要与接口层一致
{
SqlHelper sqlhelper = new SqlHelper();
SqlParameter[] sqlParams = {
new SqlParameter ("@UserName",userInfo.UserName),
new SqlParameter(@"PassWord",userInfo.PassWord)};
string sql = @"SELECT * FROM Users WHERE UserName = @UserName AND Password = @Password ";
DataTable table = sqlhelper.ExecuteQuery(sql, sqlParams, CommandType.Text);
return table;//返回的是一个table类型
}
}
}
SqlHelper
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Data.SqlClient;//数据库？
using System.Data;//表示对ADO.NET结构类的访问
using System.Configuration;//配置文件
namespace DAL
{
public class SqlHelper
{
private SqlConnection conn = null;
private SqlCommand cmd = null;
private SqlDataReader sdr = null;//只读
public SqlHelper()
{
string connStr = ConfigurationManager.AppSettings["connStr"];
//Configuration提供对客户端应用程序配置文件的访问
conn = new SqlConnection(connStr);
}
private SqlConnection GetConn()
{
if(conn.State == ConnectionState.Closed)
{
conn.Open();
}
return conn;
}
public DataTable ExecuteQuery(string cmdText, SqlParameter [] paras, CommandType ct)
{
DataTable dt = new DataTable();
cmd = new SqlCommand(cmdText, GetConn());
//CmdText查询的文本，getConn是上边的一个sqlconnection表示到sql 的连接
cmd.CommandType = ct;
//如何解释CommandText属性，CommandText指的具体的什么指令
cmd.Parameters.AddRange(paras);
using (sdr = cmd.ExecuteReader(CommandBehavior .CloseConnection ))
//ExecuteReader CommandBehavior将Commandtext发送到Connection
//并且使用CommandBeHavivor值之一生成SQLDataReader
{
dt.Load(sdr);
//填充DataTable使用所提供的数据源中的值DataReader
}
return dt;
//返回的是一个表
}
}
}