c# - 暂停一个新的 BackGroundWorker 直到上一个完成

Question

我正在为线程而苦苦挣扎。问题是当我通过 foreach 循环进行迭代时。

当设置 this.Document 时，应用程序执行登录，这是由事件触发的，需要几秒钟才能完成。在 worker_RunWorkerCompleted 方法中，我需要执行一些取决于当前登录信息的操作。

问题是，在我可以对第一个文件执行此操作之前，this.Document 已经更改，使应用程序执行另一次登录。这样我就永远无法真正执行我的操作。

我的问题是:如何暂停下一个线程，直到上一个线程完成。我的问题还有其他解决方案吗？

我尝试使用 AutoResetEvent 但我没有成功。我在 RunWorkerAsync 调用之后设置 waitOne() 并在 RunWorkerCompleted 中设置 .Set()。代码永远不会到达 RunWorkerCompleted...

代码如下:

    public void Start(object obj)
    {
       try
       {
          foreach (KeyValuePair<string, Stream> pair in this.CollectionOfFiles)
          {
              Worker = new BackgroundWorker();
              Worker.DoWork += new DoWorkEventHandler(worker_DoWork);
              Worker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(worker_RunWorkerCompleted);

          using (Stream stream = pair.Value)
              {
                primaryDocument = new Document(stream);

                DataHolderClass dataHolder = new DataHolderClass();
                dataHolder.FileName = pair.Key;
                dataHolder.Doc = secondaryDocument;

               //background thread call
                Worker.RunWorkerAsync(dataHolder);
              }
            }
          }

       catch (Exception ex)
       {
          // exception logic
}
       finally
       {
          // complete logic
       }
    }


    private void worker_DoWork(object sender, DoWorkEventArgs e)
    {
       DataHolderClass dataHolder = ((DataHolderClass)e.Argument);
       // setting this attribute triggers execution of login event
       this.Document = dataHolder.Doc;
       e.Result = (dataHolder);
    }


    private void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {
       // here I need to perform some actions that are depending on the current login
       DataHolderClass dataHolder = ((DataHolderClass)e.Result);
       this.eventAggregator.GetEvent<ActionEvent>().Publish(new Message(EMessageType.Info) { Title = dataHolder.FileName });
    }

Answer 1

9号，

尝试以下操作:

System.Threading.ManualResetEvent _busy = new System.Threading.ManualResetEvent(false);

void ResumeWorker() 
{
     // Start the worker if it isn't running
     if (!backgroundWorker1.IsBusy) backgroundWorker1.RunWorkerAsync(dataHolder);  
     // Unblock the worker 
     _busy.Set();
}

void PauseWorker() 
{
    // Block the worker
    _busy.Reset();
}

void CancelWorker() 
{
    if (backgroundWorker1.IsBusy) {
        // Set CancellationPending property to true
        backgroundWorker1.CancelAsync();
        // Unblock worker so it can see that
        _busy.Set();
    }
}

然后在您的代码中运行该方法。

让我知道它是否有效:)