C# Opening a new form and closing the other one

Question

In my program I show a login form before the main form, once the program detects a successful login I use this:

MainForm Main = new MainForm();
Main.Show();
this.Hide();

This works fine but there is a problem, the login form is still open even though it is hidden so when the program is closed the process still hangs, how can I stop this from happening?

Sorry, forgot to add, using this.Close(); doesn't work and will completely close the program.

Answer 1

Try something more like this:

this.Hide();
Main.ShowDialog();
this.Close();

You want to hide the login form before you show the dialog, then close the login form after the dialog has been closed.

Simply closing the Login dialog will ultimately end the application, so that's not a real solution, but you still want to hide the login.

Simply put, put things in the order you want them to go in, especially when dealing with message loops.

First, you hide the login form.
Next, you show the Main form dialog, but prevent the caller of "ShowDialog()" from continuing until the dialog is closed.
Last, once the dialog is closed, you close the login form, ending the application.

Answer 2

You need to specify your MainForm when you staring application and in the Load event handler of this form ask for login. In this case you will have runned application and Login for on the starting:

Program.cs

    Application.Run(new MainForm());

MainForm.cs

    private void Form1_Load(object sender, EventArgs e)
    {
        LoginForm loginForm = new LoginForm();
        if (loginForm.ShowDialog() == System.Windows.Forms.DialogResult.OK)
        {
            // check login here
        }
    }

P.S. Close will close your application completelly if it's main form of your application.