区别在WinForm中点击关闭还是执行Form.Close()

protected override void WndProc(ref Message msg)
{ 
        const int WM_SYSCOMMAND = 0x0112; 
        const int SC_CLOSE = 0xF060;  
  
         if (msg.Msg == WM_SYSCOMMAND && ((int)msg.WParam == SC_CLOSE)) 
         { 
                 // Doing Something 

                 return;
         } 
         base.WndProc(ref msg); 
}