关闭winform 弹窗的方法

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    public static int BM_CLICK = 0xf5;

//关闭winform 弹窗的方法
 private void button3_Click(object sender, EventArgs e)
        {
            Thread thread = new Thread(fff);
            thread.Start();
            Thread.Sleep(2000);
            int hwnd = FindWindow(null, "this");
            hwnd = FindWindowEx(hwnd, 0, "Button", "确定");

            IntPtr intPtr1 = SendMessage(hwnd, BM_CLICK, 0, 0);
        }