Event when a window gets maximized/un-maximized

Question

Is there an event that is fired when you maximize a Form or un-maximize it?

Before you say Resize or SizeChanged: Those get only fired if t

Answer 1

A complete solution with maximize, minimize, restore and correct remove of the lower bits which are used for internal purposes only.

protected override void WndProc(ref Message m)
{
    const int WM_SYSCOMMAND = 0x0112;
    const int SC_MAXIMIZE = 0xF030;
    const int SC_MINIMIZE = 0xF020;
    const int SC_RESTORE = 0xF120;

    // dependig on the needs may be called before, after or even never (see below)
    // base.WndProc(ref m);

    if (m.Msg == WM_SYSCOMMAND)
    {
        /// 
        /// Quote:
        /// In WM_SYSCOMMAND messages, the four low - order bits of the wParam parameter 
        /// are used internally by the system.To obtain the correct result when testing 
        /// the value of wParam, an application must combine the value 0xFFF0 with the 
        /// wParam value by using the bitwise AND operator.
        int wParam = (m.WParam.ToInt32() & 0xFFF0);

        Debug.WriteLine($"Received param: { Convert.ToString(wParam, 16) } ");

        if (wParam == SC_MAXIMIZE)
        {

        }

        if (wParam == SC_MINIMIZE)
        {

        }

        if (wParam == SC_RESTORE)
        {

        }
    }

    // don't use when above call is uncommented
    base.WndProc(ref m);
}