如何正确取消并重新启动BackgroundWorker进程？

using System.ComponentModel;

BackgroundWorker worker = new BackgroundWorker();

worker.WorkerReportsProgress = true;
worker.WorkerSupportsCancellation = true;

worker.DoWork += new DoWorkEventHandler(worker_DoWork);
worker.ProgressChanged += new ProgressChangedEventHandler(worker_ProgressChanged);
worker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(worker_RunWorkerCompleted);

void worker_DoWork(object sender, DoWorkEventArgs e)
{
    // 在这里编写需要在后台运行的代码
}

worker.ReportProgress(progressPercentage);

void worker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
    // 在这里处理后台进程报告的进度
}

void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
    // 在这里处理后台进程完成后的操作
}

worker.CancelAsync();

void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
    if (e.Cancelled)
    {
        // 后台进程已被取消
    }
    else
    {
        // 后台进程已完成
    }
}

worker.RunWorkerAsync();