/// /// 窗口类名(例：Button) /// 窗口标题 /// [DllImport("user32.dll", EntryPoint = "FindWindow")] private extern static IntPtr FindWindow(string lpClassName, string lpWindowName); ///

/// 找到窗口 ///

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

/// 发送消息 ///

/// 消息接受窗口句柄 /// 消息 /// 指定附加的消息特定信息 /// 指定附加的消息特定信息 /// [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;

通过窗体标题，循环查找该窗体，然后找到确定按钮，通过句柄发送点击消息，主动关闭弹窗

 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();