windows的消息机制

 protected override void DefWndProc(ref Message m) {
            switch (m.Msg) {
                case WM_SIZE:
                    if(m.WParam.ToInt32() == SIZE_MAXIMIZED) {
                        // 窗体最大化
                        Console.WriteLine("Maxmized");
                    }else if(m.WParam.ToInt32() == SIZE_MINIMIZED) {
                        // 窗体最小花
                        Console.WriteLine("Minimized");
                    }else 
                        // 其他
                        base.DefWndProc(ref m);
                    }
                    break;
                default:
                    base.DefWndProc(ref m);
                    break;
            }
        }

        private const int WM_SIZE = 0x0005;
        const int SIZE_MAXIMIZED = 2;
        const int SIZE_MINIMIZED = 1;