What message is called when the X in the upper right of a dialog is closed

[Dan Neely]

I need to do some cleanup when my dialog closes. I tried overriding mydialog.Close() doing the cleanup there and then calling base.Close(). When the user exits it using the close button everything works as intended, but the X doesn't call Close() and leaves my app in a messedup state.

[Mohamad Al Husseiny]

The Windows recive WM_SYSCOMMAND Notification when you close minimize or maximize the window or you choose any command from the system menu So overrid your form WndProc function and handle it

const int WM_SYSCOMMAND  = 0x0112;
const int SC_CLOSE    =    0xF060;

protected override void WndProc(ref Message m)
{
if(m.Msg==WM_SYSCOMMAND)
{
if(m.WParam.ToInt32()==SC_CLOSE)
{
MessageBox.Show("Application will be close");
// call the default after you handle it
base.WndProc(ref m);
}
}
else
{
base.WndProc (ref m);
}
}

if you don not handle other Message you can write it like

protected override void WndProc(ref Message m)
{
if(m.Msg==WM_SYSCOMMAND)
{
if(m.WParam.ToInt32()==SC_CLOSE)
{
MessageBox.Show("Application will be close");
}

}
    base.WndProc (ref m);

}

for more information look at WM_SYSCOMMAND Notification[^] MCAD -- modified at 18:53 Friday 23rd September, 2005

[mav northwind]

You should handle the Closing event of System.Windows.Forms.Form. This event is fired regardless of whether the dialog was closed via the system menu or a close button on your form. Regards, mav

[Dan Neely]

*blush* In my defense I can only say Friday 4pm.