Zimogorov_Arseniy_OrdersManager/LoginForm.cs

using System;
using System.Windows.Forms;

namespace WindowsFormsApp4
{
    public partial class LoginForm : Form
    {
        public LoginForm()
        {
            InitializeComponent();
            AttachEventHandlers();
        }

        private void AttachEventHandlers()
        {
            btnLogin.Click += BtnLogin_Click;
            btnBack.Click += BtnBack_Click;
        }

        private void BtnLogin_Click(object sender, EventArgs e)
        {
            string login = txtLogin.Text.Trim();
            string password = txtPassword.Text;

            if (string.IsNullOrEmpty(login) || string.IsNullOrEmpty(password))
            {
                MessageBox.Show("Введите логин и пароль", "Ошибка",
                    MessageBoxButtons.OK, MessageBoxIcon.Warning);
                return;
            }

            var user = DatabaseHelper.Authenticate(login, password);

            if (user != null)
            {
                Session.CurrentUser = user;
                MessageBox.Show($"Добро пожаловать, {user.FirstName} {user.LastName}!",
                    "Успешно", MessageBoxButtons.OK, MessageBoxIcon.Information);

                MainForm mainForm = new MainForm();
                mainForm.Show();
                this.Hide();

             
            }
            else
            {
                MessageBox.Show("Неверный логин или пароль",
                    "Ошибка авторизации", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }

        private void BtnBack_Click(object sender, EventArgs e)
        {
            StartForm startForm = new StartForm();
            startForm.Show();
            this.Close();
        }
    }
}