BackgroundWorker第一次工作，但第二次失败

Question

我在实现BackgroundWorker类时遇到了一个奇怪的问题。它在我的程序中运行一些测试（对于一些对这个问题不重要的硬件）。这是我为BackgroundWorker编写的代码：

public AllTests(MainMenu p)
    {
        InitializeComponent();
        WindowStartupLocation = WindowStartupLocation.CenterScreen;
        this.parent = p;
        generateCaseLabels(tc.getTCs());
        var testThread = new BackgroundWorker();
        // Tell the testthread what to do
        testThread.DoWork += (sender, args) =>
        {
            List<BaseTestCase> cases = tc.getTCs();
            foreach ( BaseTestCase test in cases )
            {
                test.execute();
                while (!test.Done) { Thread.Sleep(500); }
                if (test.Passed)
                {
                    passed.Add(test);
                }
                else
                {
                    failed.Add(test);
                }
            }
        };
        // Start the TestReport after the testing is completed
        testThread.RunWorkerCompleted += (sender, args) =>
        {
            TestReport newWindow = new TestReport(parent, passed, failed);
            testThread.CancelAsync(); // reset the testThread (?)
            log.append(this, "--- DONE TESTING --------------------");
            newWindow.Show();
            this.Close();
        };
        // Start the testthread
        testThread.WorkerSupportsCancellation = true;
        testThread.RunWorkerAsync();
    }

该代码发生的奇怪之处在于，当第一次启动时，它工作得很好，但当再次导航到此AllTests窗口时，TestReport窗口会立即打开，表明testThread.RunworkerCompleted会立即被调用。所以我的问题是：有人知道重置BackgroundWorker或其他什么聪明的方法吗，或者对这种奇怪的行为有答案吗？

顺便说一句，以下是我如何调用AllTests窗口：

 private void startTests(object sender, RoutedEventArgs e)
    {
        log.append(this, "--- STARTING ALL TESTS --------------------");
        AllTests newWindow = new AllTests(parent);
        newWindow.Show(); this.Close(); 
    }

谢谢你的帮助！罗伯特。

PS如果我有拼写错误或问题不够清楚；请原谅，英语不是我的母语，这是我在StackOverflow上的第一篇帖子！谢谢

Answer 1

这取决于如何关闭"AllTests"窗口。例如，在这个简化的测试中，它工作并每次调用后台工作程序：

// simple main form with a button to open the 2nd form
public partial class MainWindow : Window
{
    public MainWindow() { InitializeComponent(); }
    private void Button_Click(object sender, RoutedEventArgs e) { new PopupWindow().Show(); }
}
// 2nd popup window constructor (hence background worker) fires after form is closed and re-opened from the main form
public partial class PopupWindow : Window
{
    public PopupWindow()
    {
        InitializeComponent();
        WindowStartupLocation = WindowStartupLocation.CenterScreen;
        var testThread = new BackgroundWorker();
        {
            testThread.DoWork += (sender, args) => { MessageBox.Show("doWork running"); };
            testThread.RunWorkerCompleted += (sender, args) => { MessageBox.Show("doWork completed"); };
            testThread.WorkerSupportsCancellation = true;
            testThread.RunWorkerAsync();
        }
    }
}