c# - 如何在 RunWorkerCompletedEventArgs 对象中设置 UserState？

Question

大家好。我有一组运行 Worker 类实例的 BackgroundWorker 对象。当我调用 Worker 类时，对象实例会执行它，然后用完代码(循环结束)。我能够收听 RunWorkerCompleted() 事件，但是当它调用我设置的委托(delegate)时，我需要知道我的哪些 Worker 对象刚刚完成。

我在委托(delegate)的 RunWorkerCompletedEventArgs 中看到一个 UserState 属性，但我不知道如何在我的 Worker 对象中设置它，因为它正在完成。

有什么想法吗？

我的 WorkManager.cs 类的片段

public Worker AddWorker()
{
    Worker w = new Worker();

    _workers.Add(w.WorkerID,w);

    BackgroundWorker bg = new BackgroundWorker();
    _bgworkers.Add(bg);

    bg.DoWork += w.Start;
    bg.WorkerReportsProgress = true;
    bg.WorkerSupportsCancellation = true;
    bg.ProgressChanged += ProcessWorkerMessage;
    bg.RunWorkerCompleted += WorkerFinished;


    w.WorkManager = this;
    w.BackgroundWorker = bg;

    bg.RunWorkerAsync(w);


    return w;

}


public void WorkerFinished(object sender, RunWorkerCompletedEventArgs e)
{
    if (_onManagerEvent != null)
        _onManagerEvent(new ManagerEvent { EventDate = DateTime.Now, Message = "Worker ??? successfully ended." });
}

因此，当我的 Worker 对象在其 Start() 方法中完成循环时，我该如何填充传递到我的 WorkerFinished 方法 () 的 RunWorkerCompleteEventArgs 对象“e”的 userState 属性？

谢谢

Answer 1

Worker 类的Start 方法可以设置DoWorkEventArgs 参数的Result 属性。这是一个例子:

void Start(object sender, DoWorkEventArgs e)
{
   //Do your loop and other work.
   e.Result = this;
}

然后在完成事件处理程序中，您可以检索 e.Result:

public void WorkerFinished(object sender, RunWorkerCompletedEventArgs e)
{
    //You should always check e.Cancelled and e.Error before checking e.Result!
    // ... even though I'm skipping that here

    Worker w = e.Result as Worker;
    if( w != null)
    {
        if (_onManagerEvent != null)
            _onManagerEvent(new ManagerEvent 
                    { 
                      EventDate = DateTime.Now, 
                      Message = String.Format("Worker {0} successfully ended."
                                              , w.ToString()) 
                    });
    }
}