Winform窗体屏蔽Alt+F4强制关闭

/// <summary>
        /// 窗体屏蔽 ALT+F4组合键强制关闭
        /// </summary>
        protected override CreateParams CreateParams
        {
            get
            {
                const int CS_NOCLOSE = 0x200; 
                CreateParams cp = base.CreateParams; 
                cp.ClassStyle = cp.ClassStyle | CS_NOCLOSE; 
                return cp;
            }
        }