C#,winform取消右上角关闭按键

　　　　 /// <summary>
        /// 界面关闭键失效
        /// </summary>
        protected override CreateParams CreateParams
        {
            get
            {
                int CS_NOCLOSE = 0x200;
                CreateParams parameters = base.CreateParams;
                parameters.ClassStyle |= CS_NOCLOSE;
                return parameters;
            }
        }