c#
        private void KeyPress(object sender, KeyEventArgs e)
        {
            if (e.Key == Key.Return) // Check if Enter key is pressed
            {
                if (sender is Login login)
                {
                    if (login.PasswordBox.Password == MasterKey)                        

                    {
                        mainWindow.Show();
                        login.Close(); // Close the login window
                    }
                    else
                    {
                        MessageBox.Show("Incorrect MasterKey.", "Error", MessageBoxButton.OK);
                    }
                }
            }
        }

c#
        private void KeyPress(object sender, KeyEventArgs e)
        {
            if (e.Key == Key.Return) // Check if Enter key is pressed
            {
                if (sender is Login login)
                {
                    if (login.PasswordBox.Password == MasterKey)                        

                    {
                        mainWindow.Show();
                        login.Close(); // Close the login window
                    }
                    else
                    {
                        MessageBox.Show("Incorrect MasterKey.", "Error", MessageBoxButton.OK);
                    }
                }
            }
        }