根据类名和窗口名操作窗体

/// <summary>
        /// 根据类名和窗口名获取句柄
        /// </summary>
        /// <param name="lpClassName"></param>
        /// <param name="lpWindowName"></param>
        /// <returns></returns>
        [DllImport("user32.dll")]
        public static extern IntPtr FindWindow(string lpClassName, string lpWindowName);
        /// <summary>
        /// 给窗口发送消息
        /// </summary>
        /// <param name="hwnd"></param>
        /// <param name="wMsg"></param>
        /// <param name="wParam"></param>
        /// <param name="lParam"></param>
        /// <returns></returns>

        [DllImport("user32.dll", EntryPoint = "SendMessage")]
        private static extern int SendMessage(IntPtr hwnd, int wMsg, int wParam, int lParam);
        private void button1_Click(object sender, EventArgs e)
        {
            IntPtr str = FindWindow("#32770", "CmIDCard");
            SendMessage(str, 0x10, 0, 0);//关闭窗体
        }