WinForm 按ESC 提示是否要关闭

        //按ESC 提示是否要退出        protected override bool ProcessCmdKey(ref System.Windows.Forms.Message msg, System.Windows.Forms.Keys keyData) //激活回车键        {            int WM_KEYDOWN = 256;            int WM_SYSKEYDOWN = 260;            if (msg.Msg == WM_KEYDOWN | msg.Msg == WM_SYSKEYDOWN)            {                switch (keyData)                {                    case Keys.Escape:                        if (MessageBox.Show("确定要退出么？", "信息提示", MessageBoxButtons.YesNo, MessageBoxIcon.Information) == DialogResult.Yes)                        {                            this.Close();//csc关闭窗体                        }                        break;                    case Keys.Enter:                        MessageBox.Show("wakaka");                        break;                }            }            return false;        }