How to Prevent the App from Terminating When I Close the Startup Form

How do I prevent the app from terminating when I close the startup form?

The auto-generated code in Program.cs was written to terminate the application when the startup window is closed. You'll need to tweak it so it only terminates when there are no more windows left. Like this:

    [STAThread]
    static void Main() {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        var main = new Form1();
        main.FormClosed += new FormClosedEventHandler(FormClosed);
        main.Show();
        Application.Run();
    }

    static void FormClosed(object sender, FormClosedEventArgs e) {
        ((Form)sender).FormClosed -= FormClosed;
        if (Application.OpenForms.Count == 0) Application.ExitThread();
        else Application.OpenForms[0].FormClosed += FormClosed;
    }

startup form.close and application.exit not terminating app

You need an Exit While after the Forms.Application.Exit.

Application.Exit still allows the threads to finish what they are doing, and since you are effectively in an infinite loop it will never actually let the application close.

I want to leave the application when the main form is closed

if you want to exit application then add this line

 Application.Exit();

to detect if main form is closed, you need to use FormClosingEventHandler and after detecting that main form is closed, then exit application

  this.FormClosing += new System.Windows.Forms.FormClosingEventHandler(this.yourMainForm_FormClosing);


private void yourMainForm_FormClosing(object sender, FormClosingEventArgs e)
{
  //here you can exit from application 
  Application.Exit();
}

Closing and re-opening a form without closing the application

Remove your Application.Exit(). Since you are already in the FormClosing Event Handler, the Application will exit if Program.KeepRunning is set to false.

Form remains open in the background after closing it

When you write:

 Form1 x = new Form1();

you are creating a new Form1 object, so x refers to the new one and not to the original one. Instead, you could use this:

private void newTaskToolStripMenuItem_Click(object sender, EventArgs e)
{
    using (var form2 = new Form2())
    {
        this.Hide();
        form2.ShowDialog();
    }
    this.Show();
}

When ShowDialog() is called, the code following it is not executed until after the dialog box is closed, so this.Show() will execute only after Form2 is closed.

---

Related Topics