Question

I created a login form in c#.

If a user signs in with the right password and username and clicks on ‘Login’ then the second form opens. How do I close the login form after the last step?

Answer 1

Change your Main() method in Program.cs to display the login dialog. Don’t start the message loop unless a valid login was entered. For example:

static void Main() {
  Application.EnableVisualStyles();
  Application.SetCompatibleTextRenderingDefault(false);
  using (var login = new LoginForm()) {
    if (login.ShowDialog() != DialogResult.OK) return;
  }
  Application.Run(new Form1());
}

Your LoginForm should set its DialogResult property to OK if it detected a proper login.