C # Three-tier logon code tutorial,

C # Three-tier logon code tutorial,
[C #] layer-3 login Architecture

The U layer calls layer B and layer B calls layer D.

Code U Layer

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 UI {public partial class Form1: Form {public Form1 () {InitializeComponent ();} private void initialize login_click (object sender, EventArgs e) {// The display layer cannot deal with the data source. try {string userName = txtUserName. text. trim (); string password = txtPassword. text; BLL. BLL. administrator admin = new BLL. BLL. administrator (); Model. model. userInfo user = admin. userLogin (userName, password); MessageBox. show ("Login user:" + user. userName);} catch (Exception ex) {MessageBox. show (ex. message );}}}}

Layer B

Using System; using System. collections. generic; using System. linq; using System. text; using System. threading. tasks; using System. data. sqlClient; namespace BLL. BLL {public class Administrator {public Model. model. userInfo UserLogin (string userName, string password) {DAL. DAL. userDAO uDao = new DAL. DAL. userDAO (); Model. model. userInfo user = uDao. selectUser (userName, password); if (user! = Null) {DAL. DAL. scoreDAO sDao = new DAL. DAL. scoreDAO (); sDao. updateScore (user. ID, userName, 10); return user;} else {throw new Exception ("Logon Failed. ");}}}}

Layer D

Using System; using System. collections. generic; using System. linq; using System. text; using System. threading. tasks; // using System. data; // using System. data. sqlClient; namespace DAL. DAL {class DbUtil {public static string ConnString = @ "Server = .; database = Login; User ID = sa; Password = 123456 ";}} using System; using System. collections. generic; using System. linq; using System. text; using System. threading. tasks; using System. data. sqlClient; namespace DAL. DAL {public class ScoreDAO // Add 10 points {public void UpdateScore (int ID, string userName, int value) {using (SqlConnection conn = new SqlConnection (DbUtil. connString) {SqlCommand cmd = conn. createCommand (); // create a command object cmd. commandText = @ "insert into scores (ID, UserName, Score) Values (@ ID, @ UserName, @ Score)"; // modify the Score table data cmd. parameters. add (new SqlParameter ("@ ID", ID); cmd. parameters. add (new SqlParameter ("@ userName", userName); cmd. parameters. add (new SqlParameter ("@ Score", value); conn. open (); cmd. executeNonQuery () ;}}} using System; using System. collections. generic; using System. linq; using System. text; using System. threading. tasks; using System. data. sqlClient; using System. data; namespace DAL. DAL {public class UserDAO {public Model. model. userInfo SelectUser (string userName, string password) {using (SqlConnection conn = new SqlConnection (DbUtil. connString) {SqlCommand cmd = conn. createCommand (); cmd. commandText = @ "select id, UserName, Password, Email from users where UserName = @ UserName AND Password = @ Password"; cmd. commandType = CommandType. text; cmd. parameters. add (new SqlParameter ("@ UserName", userName); cmd. parameters. add (new SqlParameter ("@ Password", password); conn. open (); SqlDataReader reader = cmd. executeReader (); Model. model. userInfo user = null; while (reader. read () {if (user = null) // if not, generate a new {user = new Model. model. userInfo ();} user. ID = reader. getInt32 (0); user. userName = reader. getString (1); user. password = reader. getString (2); user. email = reader. getString (3) ;}return user ;}}}}

Model Layer

Using System; using System. collections. generic; using System. linq; using System. text; using System. threading. tasks; // transmits data between three layers without knowing the other layers. The three independent assemblies do not reference the third-layer namespace Model. model {// data is typically encapsulated. In the business logic layer, public class UserInfo {public int ID {get; set;} public string UserName {get; set;} public string Password {get; set ;}public string Email {get; set ;}}}

Tips

1. the username, password, and other information should be inserted in the user table as the original administrator.

2. After successfully logging on, log on again to delete the inserted score table data

3. regenerate the solution