Question

I try to achieve this:
i have the main form, when user click the red cross on the top right to exit the application, it popup a progress bar form indicating the application is updating/saving information. After the background worker in the progress bar form finishes, it closes the progress bar form and close the main form as well.
the problem i have is, it closes the main from first without even running the background worker. how to fix this? i tried to use e.cancel= true it just gave my dead loop.

here is my main form:

 private static void mainForm_FormClosing(object sender, FormClosingEventArgs e)
        {
 UpdatingForm pbar = new UpdatingForm ();


            pbar.Show();
}

in my updatingform:

public UpdatingForm()
        {
            InitializeComponent();

            bgWorker.RunWorkerAsync();
        }

    private void bgWorker_DoWork(object sender, DoWorkEventArgs e)
            {
    ....
    }

private void bgWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {

            this.Close();
            // Application.Exit();
        }

Answer 1

Setting e.Cancel to true is correct. However, once your UpdatingForm closes, Application.Exit() fires the mainForm_FormClosing() event again, so you get one more UpdatingForm etc.

private static bool isClosing = false;
private static void mainForm_FormClosing(object sender, FormClosingEventArgs e)
{
    if (!isClosing)
    {
        isClosing = true;
        e.Cancel = true;
        UpdatingForm pbar = new UpdatingForm ();
        pbar.Show();
    }
}