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()) 
                    });
    }
}