[REHome]

Gracias. Por ahora he hecho esto:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

using MySql.Data.MySqlClient; // No olvidar aquí.
using MySql.Data.Types;

namespace Contraseña01
{
    public partial class Form1 : Form
    {
        MySqlConnection connection = null; // No olvidar.
        string MyConString;

        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (textBox1.Text == "1234")
            {
                
                MessageBox.Show("Contraseña CORRECTA", "Aviso:",
                    MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
            else
            {
                MessageBox.Show("Contraseña INCORRECTA", "Aviso:",
                    MessageBoxButtons.OK, MessageBoxIcon.Stop);
            }
        }

        private void button_crear_db_Click(object sender, EventArgs e)
        {
            string MyConString = "SERVER=127.0.0.1;" +
                    "PORT=3306;" +
                    "UID=root;" +
                    "PASSWORD=1234;";
            string tabla = @"CREATE TABLE `guardar` (
                            `password` varchar(20) NOT NULL,
                            PRIMARY KEY (`password`)
                            ) ENGINE=InnoDB DEFAULT CHARSET=latin1;";

            connection = new MySqlConnection(MyConString);
            connection.Open();

            MySqlCommand con = new MySqlCommand(tabla, connection);
            con.ExecuteNonQuery();
        }
    }
}