使用 windows 表单将 C# 连接到 mySQL 数据库

Question

我是 C# 的新手，正在尝试将 windows 表单连接到 mySQL 数据库。问题是我收到以下错误，但找不到解决此问题的方法。

Error CS0120 An object reference is required for the non-static field, method, or property 'Login.con()

这是Form.cs

using MySql.Data.MySqlClient;
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 Log
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        public void BtnConnect_Click(object sender, EventArgs e)
        {
            Login.con();
        }
    }
}

这是应该建立连接的 Login.cs 文件。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using MySql.Data.MySqlClient;
using System.Windows.Forms;
using MySql.Data;
using System.Data;

namespace Log
{
    public class Login
    {
        public MySqlConnection connection;
        private string server;
        private string database;
        private string user;
        private string password;
        private string port;
        private string connectionString;
        private string sslM;

        public Login()
        {

            server = "localhost";
            database = "test";
            user = "root";
            password = "root";
            port = "3306";
            sslM = "none";

            connectionString = String.Format("server={0};port={1};user id={2}; password={3}; database={4}; SslMode={5}", server, port, user, password, database, sslM);

            connection = new MySqlConnection(connectionString);
        }

        public void con()
        {
            try
            {
                connection.Open();
                MessageBox.Show("successful connection");
                connection.Close();
            }
            catch (MySqlException ex)
            {
                MessageBox.Show(ex.Message + connectionString);
            }
        }
    }
}

Answer 1

您需要实例登录class...

Login login = new Login();
login.con()

Answer 2

您必须创建一个新的 class 登录实例。试一试：

public void BtnConnect_Click(object sender, EventArgs e)
{
    Login login = new Login();        
    login.con();
}

使用 windows 表单将 C# 连接到 mySQL 数据库

Connect C# to mySQL database using windows form

c#

mysql

windows-forms-designer