How to separate custom Close Button from Window_Closing?

April 13, 2022

I’m building the WPF app with multiple forms, and my goal is that, on, let’s say LoginForm I have a button called Login, which, when clicked, closes current form (LoginForm from above) and opens another form (let’s say Form1).

Note that I’m trying to have only one form opened at a time.

Code –

private void btnLogin_Click(object sender, RoutedEventArgs e)
    {
        if(everything okay)
        {
            Form1 frm = new Form1();
            frm.Show();
            Close();
        }
        else
        {
            return;
        }
    }

This works fine. But, my second idea is that, if X in the top right corner is clicked, I want to close this form, and not to open any other, basically exiting the app.

Code-

private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
    {
        MessageBoxResult rez = MessageBox.Show("Do you wish to leave the app?", "Question?", MessageBoxButton.YesNo, MessageBoxImage.Question);

        if (rez != MessageBoxResult.Yes)
        {
            e.Cancel = true;
        }
    }

This is where my problem starts, I’ve found that Window_Closing and this.Close() are same event, so, when I click the Login button, MessageBoxResult still shows up, even tho that is not my goal. I want to somehow separate those two events, if that is possible. How can I do so?

>Solution :

You could temporarily unhook the event handler just before you call Close():

private void btnLogin_Click(object sender, RoutedEventArgs e)
{
    if (everything okay)
    {
        Form1 frm = new Form1();
        frm.Show();
        Closing -= Window_Closing;
        Close();
        Closing += Window_Closing;
    }
    else
    {
        return;
    }
}

Or use a bool variable to determine whether to display the MessageBox:

private bool _showMessageBox = true;

private void btnLogin_Click(object sender, RoutedEventArgs e)
{
    if (everything okay)
    {
        Form1 frm = new Form1();
        frm.Show();
        _showMessageBox = false;
        Close();
        _showMessageBox = true;
    }
    else
    {
        return;
    }
}

private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
{
    if (!_showMessageBox)
        return;

    MessageBoxResult rez = MessageBox.Show("Do you wish to leave the app?", "Question?", MessageBoxButton.YesNo, MessageBoxImage.Question);

    if (rez != MessageBoxResult.Yes)
    {
        e.Cancel = true;
    }
}