我该如何等待BackgroundWorker？

backgroundWorker.RunWorkerAsync();
backgroundWorker.WaitForExit();

AutoResetEvent waitHandle = new AutoResetEvent(false);

backgroundWorker.RunWorkerCompleted += (sender, args) =>
{
    waitHandle.Set();
};

backgroundWorker.RunWorkerAsync();
waitHandle.WaitOne();

ManualResetEvent waitHandle = new ManualResetEvent(false);

backgroundWorker.RunWorkerCompleted += (sender, args) =>
{
    waitHandle.Set();
};

backgroundWorker.RunWorkerAsync();
waitHandle.WaitOne();

Task task = Task.Factory.StartNew(() =>
{
    backgroundWorker.RunWorkerAsync();
    while (backgroundWorker.IsBusy)
    {
        Thread.Sleep(100);
    }
});

task.Wait();