Change of Users

Question

Good evening guys I’m doing a project in college and I came across a problem a while back and I couldn’t solve it. I have the Login screen and within the system I have User Exchange and when I call the Login screen it opens another system on top with what was being used below, when I close the previous application closes everything, I made the authentication close the current screen and open a new one only that when the previous application closes it waits for the confirmation of closure yes or there is something that I can solve it ?

The code below is from the menu button calling the login screen of the user, the commented code is the test I did with an example of the internet more did not work

code:

    private void trocarUsuarioToolStripMenuItem_Click(object sender, EventArgs e)
    {
        frmLogin objLogin = new frmLogin();
        objLogin.MdiParent = this;
        objLogin.Show();

        //this.Visible = false;
        //frmLogin objLogin = new frmLogin();
        //objLogin.ShowDialog();
    }

Answer 1

There’s probably more than one way to do this, I’ll give you a basic example and you change it according to your needs.

Login Form:

using System;
using System.Windows.Forms;

namespace Aplicativo.Teste
{
    public partial class frmLogin : Form
    {
        // propriedade para indicar se a autenticação foi feita com sucesso.
        public bool Autenticado { get; private set; }

        public frmLogin()
        {
            InitializeComponent();
            Autenticado = false;
        }

        private void btnAutenticar_Click(object sender, EventArgs e)
        {
            // essa verificação é somente para exemplificar
            if (txtSenha.Text == "123456")
            {
                Autenticado = true;
                Close();
            }
            else
            {
                MessageBox.Show("Senha inválida.", "Aviso", MessageBoxButtons.OK, 
                                MessageBoxIcon.Exclamation);
                txtSenha.Focus();
            }
        }
    }
}

Menu Form:

using System;
using System.Windows.Forms;

namespace Aplicativo.Teste
{
    public partial class frmMenu : Form
    {
        // propriedade para indicar se foi feito o logoff.
        public bool Logoff { get; private set; }

        public frmMenu()
        {
            InitializeComponent();
            Logoff = false;
        }

        private void btnLogoff_Click(object sender, EventArgs e)
        {
            Logoff = true;
            Close();
        }
    }
}

Class with the method main:

using System;
using System.Windows.Forms;

namespace Aplicativo.Teste
{
    static class Program
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);

            frmLogin fLogin = null;
            frmMenu fMenu = null;
            bool logoff;

            do
            {
                logoff = false;
                fLogin = new frmLogin();

                Application.Run(fLogin);

                if (fLogin.Autenticado)
                {
                    fLogin.Dispose();
                    fLogin = null;

                    fMenu = new frmMenu();

                    Application.Run(fMenu);

                    logoff = (fMenu != null ? fMenu.Logoff : false);

                    fMenu.Dispose();
                    fMenu = null;
                }

                GC.Collect();
                GC.WaitForPendingFinalizers();

            } while (logoff);
        }
    }
}

The code is very simple and easy to understand, in case you still have any doubts leave in the comments.