[转]winform窗体屏蔽alt+F4键

/// <summary>
        /// 屏蔽Alt+F4
        /// </summary>
        /// <param name="m">要处理的 Windows </param>
        protected override void WndProc(ref Message m)
        {
            const int WM_SYSCOMMAND = 0x0112;
            const int SC_CLOSE = 0xF060;
            if (m.Msg == WM_SYSCOMMAND)
            {
                if (m.Msg == WM_SYSCOMMAND)
                {
                    if ((m.WParam.ToInt32() & 0xFFF0) == SC_CLOSE
                            && m.LParam.ToInt32() == 0)
                    {
                        return;
                    }
                }
            }
            base.WndProc(ref m);
        }

转摘自:http://www.cnblogs.com/angels/archive/2011/02/22/1960988.html