启动屏幕保护程序

实现效果:

　　

知识运用：

　　API函数SendMessage向窗口发送消息

　　private static extern bool SendMessage(IntPtr hWnd, int wMsg,int wParam,int IParam)

　　//hWnd: 窗口句柄  wMsg: 将要发送的消息  wParam,IParam :消息的参数 依据发送的消息而定

实现代码：

        private const int WM_SYSCOMMAND = 0x0112;
        private const int SC_SCREENSAVE = 0xf140;
        [DllImport("user32.dll")]
        public static extern bool SendMessage(IntPtr hWnd,int wMsg,int wParam,int IParam);
        private void button1_Click(object sender, EventArgs e)
        {
            SendMessage(this.Handle, WM_SYSCOMMAND, SC_SCREENSAVE, 0);
        }