backgroundWorker执行无限循环，CancelAsync()还能发挥作用吗？

Question

backgroundWorker对象的DowWork事件
        private void _backgroundWorkerAuto_DoWork(object sender, DoWorkEventArgs e)
        {
            Thread.Sleep(15000);
            MessageBox.Show("Do Work!");
        }
RunWorkerCompleted事件
        private void _backgroundWorkerAuto_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            MessageBox.Show("Work Complete!");
            _backgroundWorkerAuto.RunWorkerAsync();
        }
以及窗口关闭事件
        private void FileUploadTool_FormClosing(object sender, FormClosingEventArgs e)
        {
            if (MessageBox.Show("将要关闭窗体，是否继续？", "确认退出？", MessageBoxButtons.YesNo) == DialogResult.Yes)
            {
                if (_backgroundWorkerAuto.IsBusy)
                {
                    _backgroundWorkerAuto.CancelAsync();
                }
                e.Cancel = false;
            }
            else
                e.Cancel = true;
        }请问关闭程序还会遗留后台线程吗？CancelAsync()

Answer 1

如果线程没停止。是会保留的。