关闭显示器和打开显示器

        [DllImport("user32.dll")]
        public static extern IntPtr SendMessage(IntPtr hWnd, uint msg, uint wParam, int lParam);

        private const uint WM_SYSCOMMAND = 0x0112;
        private const uint SC_MONITORPOWER = 0xF170;


        //关闭显示器 
        private void button1_Click(object sender, EventArgs e)
        {
            SendMessage(this.Handle, WM_SYSCOMMAND, SC_MONITORPOWER, 2);
            //this.button2.Focus();
        }

        //打开显示器 
        private void button2_Click(object sender, EventArgs e)
        {
            SendMessage(this.Handle, WM_SYSCOMMAND, SC_MONITORPOWER, -1);
            //this.button1.Focus();
        }