从后台工作线程(调用)向列表框添加字符串

我对编码c#相当陌生，并且正在尝试使用后台工作器(以避免停止我的GUI)来运行ping循环，其结果将在我的GUI中的每个ping中打印到列表框，就像标准cmd提示符一样。

我的代码编译，但文本不出现在列表框中，任何帮助，我在哪里出错将是伟大的。

感谢

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
    {
        int secs = DateTime.Now.Second;
        while (keepgoing == true)
        {
            if (secs != DateTime.Now.Second)
            {
                secs = DateTime.Now.Second;
                using (Ping p = new Ping())
                {
                    int hh = DateTime.Now.Hour;
                    int mm = DateTime.Now.Minute;
                    int ss = DateTime.Now.Second;
                    string time = "";
                    if (hh < 10)
                    {
                        time += "0";
                        time += hh;
                    }
                    else
                    {
                        time += hh;
                    }
                    time += ":";
                    if (mm < 10)
                    {
                        time += "0";
                        time += mm;
                    }
                    else
                    {
                        time += mm;
                    }
                    time += ":";
                    if (ss < 10)
                    {
                        time += "0";
                        time += ss;
                    }
                    else
                    {
                        time += ss;
                    }
                    string successString = ("Ping Successful - " +       p.Send(textBox2.Text).RoundtripTime.ToString() + "ms    " + time + "'n");
                    Invoke((Action<string>)AddItemBox2,successString);
                }
            }
        }
        listBox2.Items.Add("'n");
    }
    private void listBox2_SelectedIndexChanged(object sender, EventArgs e)
    {
    }
    private void AddItemBox2(string print)
    {
        listBox2.Items.Add(print);
        listBox2.Refresh();
        listBox2.TopIndex = listBox2.Items.Count - 1;
    }