C#连接Mysql实现登录注册界面

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界面如上:
是一个初始登录界面,有注册和登录功能,使用mysql数据库:
注册界面:
登录界面模板:

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 = "登录中。。。请稍候";
            
            Form2 f2 = new Form2();
            f2.showuser = this.textBox1.Text.Trim();

          

            //------------------连接数据库字符串-----------------------------------
            String serverinfo = "server=your_server;" +
                "port=your_port;" +
                "user=your_username;" +
                "password=your_passwd;" +
                "database=;";
            //------------------连接数据库字符串-----------------------------------

            //异常检测
            string username = textBox1.Text.Trim();
            string passwd = textBox2.Text.Trim();

            if (username.Equals("") || passwd.Equals(""))
            
                MessageBox.Show("用户名或密码不能为空!");
            
            else
            
                MySqlConnection conn = new MySqlConnection(serverinfo); //建立连接
                try
                
                    conn.Open(); //打开
                    //建立sql语句
                    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()); //判断是否存在
                    if (resp > 0)
                    
                        label4.Text = "";
                        MessageBox.Show("登录成功!");

                       
                  
                        this.Hide();
                        f2.Show();

                        conn.Close();//关闭连接
                    
                    else
                    
                        error_time = error_time - 1;  //错误时间

                        MessageBox.Show("用户名或密码错误!!");
                        label4.Text = "";
                    
                
                catch (Exception ex)
                
                    MessageBox.Show("出现了未知的错误,请联系管理员.");
                    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();
        
    


注册界面:

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 = "注册中。。。请稍候";
            //------------------连接数据库字符串-----------------------------------
            String serverinfo = "server=your_server;" +
                "port=your_port;" +
                "user=your_username;" +
                "password=your_passwd;" +
                "database=;";
            //------------------连接数据库字符串-----------------------------------



            string username = textBox1.Text.Trim();
            string passwd = textBox2.Text.Trim();  //获取输入的注册用户名和密码
            string nickname = textBox3.Text.Trim();

            MySqlConnection conn = new MySqlConnection(serverinfo); //建立连接

            try
            
                conn.Open(); //打开
                             //建立sql语句
                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()); //分别判断是否存存在
                int resp_2 = Convert.ToInt32(com_2.ExecuteScalar());
             
                if (resp_1 > 0)
                
                    MessageBox.Show("用户名已存在!请重新输入!");
                    label5.Text = "";
                
                else
                
                    if(resp_2 > 0)
                    
                        MessageBox.Show("昵称已存在,请重新输入");
                        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();  //执行

                        MySqlCommand com_4 = new MySqlCommand(sql_1, conn); //检验数据库里是否加入了注册数据
                        com_4.ExecuteNonQuery();  //执行

                        int resp_4 = Convert.ToInt32(com_4.ExecuteScalar());
                        com_3 = null;
                        if (resp_4 > 0)
                        

                            MessageBox.Show("恭喜! " + nickname + ",注册成功,快去登陆吧!");
                            label5.Text = "";
                            Form1 f1 = new Form1();
                            this.Hide();                      
                            f1.Show();
                        
                        else
                        
                            MessageBox.Show("注册失败!请重试!");
                            label5.Text = "";

                        
                    
                    
                
                conn.Close();//最后关闭连接
            
            catch (Exception ex)
            
                MessageBox.Show("出现了未知的错误,请联系管理员.");
                label5.Text = "";
            
        

        private void Form3_Load(object sender, EventArgs e)
        

        
    
 


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