如何使主窗体仅在用户从第二个窗体成功登录时才显示？

// LoginForm.cs
public partial class LoginForm : Form
{
    public LoginForm()
    {
        InitializeComponent();
    }

    private void loginButton_Click(object sender, EventArgs e)
    {
        // 假设验证逻辑为用户名为admin，密码为password的情况下通过
        string username = usernameTextBox.Text;
        string password = passwordTextBox.Text;

        if (username == "admin" && password == "password")
        {
            MessageBox.Show("登录成功！");
            MainWindow mainWindow = new MainWindow();
            mainWindow.Show();
            this.Hide();
        }
        else
        {
            MessageBox.Show("登录失败，请检查用户名和密码！");
        }
    }
}

// MainWindow.cs
public partial class MainWindow : Form
{
    public MainWindow()
    {
        InitializeComponent();
    }
}