C#后台工作者如何报告字符串？

Question

我如何从BackgroundWorker返回一个字符串（例如“正在搜索文件……”、“找到选择……”）和进度百分比到我的Windows Form？此外，我有一个包含我想要在BackgroundWorker_Work中运行的方法的大类。我可以通过Class_method()调用它，但是我无法从被调用的类报告百分比完成或任何其他信息，只能从BackgroundWorker_Work方法中报告。

谢谢！

- nona urbiz

Answer 1

我假设WCF也拥有这个方法

public void ReportProgress(int percentProgress, Object userState); 

所以只需使用userState报告字符串即可。

private void worker_DoWork(object sender, DoWorkEventArgs e)
{
 //report some progress
 e.ReportProgress(0,"Initiating countdown");

// initate the countdown.
}

你将在ProgressChanged事件中获得"Initiating countdown"字符串。

private void worker_ProgressChanged(object sender,ProgressChangedEventArgs e) 
{
  statusLabel.Text = e.UserState as String;
}

- nos

Answer 2

您可以使用ReportProgress方法的userState参数来报告这些字符串。以下是MSDN上的一个示例：

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
    // This method will run on a thread other than the UI thread.
    // Be sure not to manipulate any Windows Forms controls created
    // on the UI thread from this method.
    backgroundWorker.ReportProgress(0, "Working...");
    Decimal lastlast = 0;
    Decimal last = 1;
    Decimal current;
    if (requestedCount >= 1)
    { AppendNumber(0); }
    if (requestedCount >= 2)
    { AppendNumber(1); }
    for (int i = 2; i < requestedCount; ++i)
    {
        // Calculate the number.
        checked { current = lastlast + last; }
        // Introduce some delay to simulate a more complicated calculation.
        System.Threading.Thread.Sleep(100);
        AppendNumber(current);
        backgroundWorker.ReportProgress((100 * i) / requestedCount, "Working...");
        // Get ready for the next iteration.
        lastlast = last;
        last = current;
    }

    backgroundWorker.ReportProgress(100, "Complete!");
}

- RaYell

Answer 3

阅读Windows Forms中的简单多线程。

这是一个三部分系列。

- Cheeso

Answer 4

使用委托。

- Ganesh R.