test/KursovayaDvornikovAM/LoginForm.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;
using static System.Windows.Forms.VisualStyles.VisualStyleElement;

namespace KursovayaDvornikovAM
{
    public partial class LoginForm : Form
    {
        public LoginForm()
        {
            InitializeComponent();
        }

            private void CloseButton_Click(object sender, EventArgs e)
            {
                Application.Exit();
            }

            private void CloseButton_MouseEnter(object sender, EventArgs e)
            {
                CloseButton.ForeColor = Color.Red;
            }

            private void CloseButton_MouseLeave(object sender, EventArgs e)
            {
                CloseButton.ForeColor = Color.Black;
            }

            Point lastPoint;
            private void LoginForm_MouseMove(object sender, MouseEventArgs e)
            {
                if (e.Button == MouseButtons.Left)
                {
                    this.Left += e.X - lastPoint.X;
                    this.Top += e.Y - lastPoint.Y;

                }
            }

            private void LoginForm_MouseDown(object sender, MouseEventArgs e)
            {
                lastPoint = new Point(e.X, e.Y);
            }

            private void buttonLogin_Click(object sender, EventArgs e)
            {

                string connectionString = "server=cfif31.ru;user=ISPr24-37_DvornikovAM;database=ISPr24-37_DvornikovAM_Kursovaya;password=ISPr24-37_DvornikovAM;";
                MySqlConnection DBconnection = new MySqlConnection(connectionString);
                MySqlCommand command = new MySqlCommand("SELECT * FROM `ISPr24-37_DvornikovAM_Kursovaya`.Polzovatel WHERE Login = @login and Password=@password;", DBconnection);
                command.Parameters.AddWithValue("@login", LoginField.Text);
                command.Parameters.AddWithValue("@password", PassField.Text);
                DBconnection.Open();
                MySqlDataReader reader = command.ExecuteReader();
               if (reader.HasRows)
               {

                 MainForm main = new MainForm();
                 main.Show();
                 this.Hide();
               }
               else
               {
                MessageBox.Show("Неверный логин или пароль!");
               }
            reader.Close();
            DBconnection.Close(); 
            }

            private void RegisterLabel_Click(object sender, EventArgs e)
            {
                this.Hide();
                RegisterForm registerForm = new RegisterForm();
                registerForm.Show();
            }

        private void HideButton_Click(object sender, EventArgs e)
        {
            this.WindowState = FormWindowState.Minimized;
        }

        private void HideButton_MouseEnter(object sender, EventArgs e)
        {
            HideButton.ForeColor = Color.Red;
        }

        private void HideButton_MouseLeave(object sender, EventArgs e)
        {
            HideButton.ForeColor = Color.Black;
        }

        private void LoginField_TextChanged(object sender, EventArgs e)
        {

        }
    }
}