禁用和启用windows form窗体上的关闭按钮

 1public partial class Form1 : Form
 2    {
 3        private bool isEnableCloseButton = false;
 4        public Form1(string strFlag)
 5        {
 6            InitializeComponent();
 7            if (strFlag == "no")
 8            {
 9                this.lbl_CloseButtonIsEnabled.Text = "窗体右上角关闭按钮无效";
                this.isEnableCloseButton = false;
            }
            else
            {
                this.lbl_CloseButtonIsEnabled.Text = "可以通过窗体右上角关闭按钮 关闭窗体";
                this.isEnableCloseButton = true;
            }
        }

        protected override CreateParams CreateParams
        {
            get
            {
                if (isEnableCloseButton)
                {
                    CreateParams parameters = base.CreateParams;
                    return parameters;
                }
                else
                {
      int CS_NOCLOSE = 0x200;
                    CreateParams parameters = base.CreateParams;
                    parameters.ClassStyle |= CS_NOCLOSE;
                    return parameters;                    
                }
            }
        }
}