How to open my "logged in" main form, by clicking a button from another Form? and without login again

Question

public partial class Menu : Form
    {

        // this is my main form, What I really want 
        //is not re-enter my name and password
        //when I call this form from another form button.
        public Menu()
        {

            InitializeComponent();

            {

            }
            unidadesToolStripMenuItem.Enabled = false;
            materialesToolStripMenuItem.Enabled = false;
            datosToolStripMenuItem.Enabled = false;
            chequeoToolStripMenuItem.Enabled = false;
            informeToolStripMenuItem.Enabled = false;
            proyectoToolStripMenuItem.Enabled = false;
        }

       // public void MenuDatosComb();
       // if()

        public bool UsuarioLogueado = false;
        private void Menu_Load(object sender, EventArgs e)
        {

            this.Hide();
            Login login = new Login();
            login.ShowDialog();
            if (login.Logueado == true)
            {
                this.Show();
                UsuarioLogueado = true;
                toolStripStatusLabel2.Text = "Usuario: " + login.Resultado.Substring(20);
            }
            else
            {
                this.Close();
            }
        }

Answer 1

Try this approach, not the best but will work for you.

In the Login Form, add a static property like this

public static bool Logueado { get; private set; }

Then in the Login Form, when the user connects successfuly, you set Logueado = true;

Now in your Main Form, in the load event, you just do this :

this.Hide();
if (Login.Logueado == true)
{
    // show
}
else
    // close

With this, you'll not need to create a new Login form in the load event, thus, you'll not get another login form.