C#根据弹窗标题获取窗体句柄并模拟点击按钮（FindWindow，FindWindowEx，SendMessage）

        /// <summary>
        /// 找到窗口
        /// </summary>
        /// <param name="lpClassName">窗口类名(例：Button)</param>
        /// <param name="lpWindowName">窗口标题</param>
        /// <returns></returns>
        [DllImport("user32.dll", EntryPoint = "FindWindow")]
        private extern static IntPtr FindWindow(string lpClassName, string lpWindowName);

        /// <summary>
        /// 找到窗口
        /// </summary>
        /// <param name="hwndParent">父窗口句柄（如果为空，则为桌面窗口）</param>
        /// <param name="hwndChildAfter">子窗口句柄（从该子窗口之后查找）</param>
        /// <param name="lpszClass">窗口类名(例：Button</param>
        /// <param name="lpszWindow">窗口标题</param>
        /// <returns></returns>
        [DllImport("user32.dll", EntryPoint = "FindWindowEx")]
        private extern static IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpszClass, string lpszWindow);

        /// <summary>
        /// 发送消息
        /// </summary>
        /// <param name="hwnd">消息接受窗口句柄</param>
        /// <param name="wMsg">消息</param>
        /// <param name="wParam">指定附加的消息特定信息</param>
        /// <param name="lParam">指定附加的消息特定信息</param>
        /// <returns></returns>
        [DllImport("user32.dll", EntryPoint = "SendMessageA")]
        private static extern int SendMessage(IntPtr hwnd, uint wMsg, int wParam, int lParam);

        //窗口发送给按钮控件的消息，让按钮执行点击操作，可以模拟按钮点击
        private const int BM_CLICK = 0xF5;

 private void Form1_Load(object sender, EventArgs e)
        {
            Task task = new Task(() =>
            {
                while (true)
                {
                    //测试警告框
                    IntPtr maindHwnd = FindWindow(null, "提示");//主窗口标题
                    if (maindHwnd != IntPtr.Zero)
                    {
                        IntPtr childHwnd = FindWindowEx(maindHwnd, IntPtr.Zero, null, "确定");//按钮控件标题
                        if (childHwnd != IntPtr.Zero)
                        {
                            SendMessage(childHwnd, BM_CLICK, 0, 0);
                        }
                    }
                }
            });

            task.Start();
        }