The interface is as above :
It's an initial login interface , There are registration and login functions , use mysql database :
Registration interface :
Login interface template :

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; using
MySql.Data.MySqlClient; using System.Data.SqlClient; namespace
WinForms_Medicine_test { public partial class Form1 : Form { private int
error_time = 3; public Form1() { InitializeComponent(); } private void
textBox1_TextChanged(object sender, EventArgs e) { } private void
button1_Click(object sender, EventArgs e) { label4.Text = " Logging in ... please wait a moment "; Form2 f2
= new Form2(); f2.showuser = this.textBox1.Text.Trim();
//------------------ Connection database string ----------------------------------- String
serverinfo = "server=your_server;" + "port=your_port;" + "user=your_username;"
+ "password=your_passwd;" + "database=;";
//------------------ Connection database string ----------------------------------- // anomaly detection string
username = textBox1.Text.Trim(); string passwd = textBox2.Text.Trim(); if
(username.Equals("") || passwd.Equals("")) { MessageBox.Show(" The user name or password cannot be empty !"); }
else { MySqlConnection conn = new MySqlConnection(serverinfo); // Make a connection try {
conn.Open(); // open // establish sql sentence string sql = "select count(*) from
userINFO.loginINFO where name = '" + username + "' and passwd = '" + passwd +
"'"; MySqlCommand com = new MySqlCommand(sql, conn); int resp =
Convert.ToInt32(com.ExecuteScalar()); // Judge whether it exists if (resp > 0) { label4.Text =
""; MessageBox.Show(" Login successful !"); this.Hide(); f2.Show(); conn.Close();// Close the connection }
else { error_time = error_time - 1; // Wrong time MessageBox.Show(" Wrong user name or password !!");
label4.Text = ""; } } catch (Exception ex) {
MessageBox.Show(" An unknown error has occurred , Please contact the administrator ."); label4.Text = ""; } } } private void
textBox2_TextChanged(object sender, EventArgs e) { } private void
label1_Click(object sender, EventArgs e) { } private void Form1_Load(object
sender, EventArgs e) { } private void button2_Click(object sender, EventArgs e)
{ Form3 f3 = new Form3(); this.Hide(); f3.Show(); } } }
Registration interface :

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; using
MySql.Data.MySqlClient; using System.Data.SqlClient; namespace
WinForms_Medicine_test { public partial class Form3 : Form { public Form3() {
InitializeComponent(); } private void label4_Click(object sender, EventArgs e)
{ } private void textBox1_TextChanged(object sender, EventArgs e) { } private
void button2_Click(object sender, EventArgs e) { Form1 f1 = new Form1();
this.Hide(); f1.Show(); } public string nickname = ""; public string username =
""; private void button1_Click(object sender, EventArgs e) { label5.Text =
" Registered ... please wait a moment "; //------------------ Connection database string -----------------------------------
String serverinfo = "server=your_server;" + "port=your_port;" +
"user=your_username;" + "password=your_passwd;" + "database=;";
//------------------ Connection database string ----------------------------------- string username
= textBox1.Text.Trim(); string passwd = textBox2.Text.Trim(); // Get the registered user name and password entered
string nickname = textBox3.Text.Trim(); MySqlConnection conn = new
MySqlConnection(serverinfo); // Make a connection try { conn.Open(); // open // establish sql sentence string
sql_1 = "select count(*) from userINFO.loginINFO where name = '"+ username+"'";
string sql_2 = "select count(*) from userINFO.loginINFO where name = '" +
nickname + "'"; MySqlCommand com_1 = new MySqlCommand(sql_1, conn);
MySqlCommand com_2 = new MySqlCommand(sql_2, conn); int resp_1 =
Convert.ToInt32(com_1.ExecuteScalar()); // Judge whether it exists or not int resp_2 =
Convert.ToInt32(com_2.ExecuteScalar()); if (resp_1 > 0) {
MessageBox.Show(" The user name already exists ! Please re-enter !"); label5.Text = ""; } else { if(resp_2 > 0) {
MessageBox.Show(" Nickname already exists , Please re-enter "); label5.Text = ""; } else { String sql_insert =
"insert into userINFO.loginINFO(name,passwd,nickname) VALUES('" + username +
"','" + passwd +"','"+nickname + "')"; MySqlCommand com_3 = new
MySqlCommand(sql_insert, conn); com_3.ExecuteNonQuery(); // implement MySqlCommand
com_4 = new MySqlCommand(sql_1, conn); // Check whether the registration data is added to the database
com_4.ExecuteNonQuery(); // implement int resp_4 =
Convert.ToInt32(com_4.ExecuteScalar()); com_3 = null; if (resp_4 > 0) {
MessageBox.Show(" congratulations ! " + nickname + ", login was successful , Go and land !"); label5.Text = ""; Form1 f1
= new Form1(); this.Hide(); f1.Show(); } else { MessageBox.Show(" login has failed ! Please try again !");
label5.Text = ""; } } } conn.Close();// Finally, close the connection } catch (Exception ex) {
MessageBox.Show(" An unknown error has occurred , Please contact the administrator ."); label5.Text = ""; } } private void
Form3_Load(object sender, EventArgs e) { } } }

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