C# WPF Login Window: Authentication with DatabaseService Example

using System.Data;
using System.Windows;

namespace WpfApp1
{
public partial class LoginWindow : Window
{
private readonly DatabaseService db = new DatabaseService();

public LoginWindow()
{
InitializeComponent();
}

private void LoginButton_Click(object sender, RoutedEventArgs e)
{
string login = LoginTextBox.Text.Trim();
string password = PasswordBox.Password.Trim();

if (login == "" || password == "")
{
MessageBox.Show("Введите логин и пароль.", "Ошибка");
return;
}

DataTable user = db.Login(login, password);

if (user.Rows.Count == 0)
{
MessageBox.Show("Неверный логин или пароль.", "Ошибка");
return;
}

string fullName = user.Rows[0]["full_name"].ToString() ?? "Пользователь";
string roleName = user.Rows[0]["role_name"].ToString() ?? "Пользователь";

MainWindow window = new MainWindow(fullName, roleName);
window.Show();
Close();
}

private void GuestButton_Click(object sender, RoutedEventArgs e)
{
MainWindow window = new MainWindow("Гость", "Гость");
window.Show();
Close();
}
}
}