How can I run a second application from another one (C#)

Question

Can you tell me how can I close a first application and immediately run a second application?

First Step: (Login validation)

static void Main()
{
    Application.EnableVisualStyles();
    Application.SetCompatibleTextRenderingDefault(false);
    Application.Run(new Login());
}

Second Step: (Run main program)

If the user succesfully logins to program, I need to close the login application and run the new application named "Main".

The check for the login is the following:

if (access.access == true)
{
    Application.Run(new Main());
    Close();
}
else
    MessageBox.Show("Přihlašovací jméno nebo heslo neni správné");

Debug Error:

Create a second message loop on a single thread is an invalid operation. Instead, use the Application.RunDialog or form.ShowDialog.

I think that the best answer for my problem is to use ShowDialog and DialogResult, but I don't know how can I use them for my settings.

Answer 1

You could run a modal dialog asking for credentials before entering the main loop

static void Main()
{
    Application.EnableVisualStyles();
    Application.SetCompatibleTextRenderingDefault(false);

    bool validated = false;
    using(frmLogin fLogin = new frmLogin())
    {
         if(fLogin.ShowDialog() == DialogResult.OK)
             validated = true;
    }
    if(validated)
        Application.Run(new Main());
    else
        MessageBox.Show("Bye");
}