c# - ReportProgress 不使用 c# 中的任务调用 progressChanged

Question

 private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
    {            
        int currentProgress=-1;

        while (currentProgress<length)
        {
            currentProgress=Worker.progress;
            backgroundWorker1.ReportProgress(currentProgress);
            Thread.Sleep(500);
            length = Worker.UrlList.Count;
        }
    }

    private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
    {
        int ix = e.ProgressPercentage;
        progressBar1.Value = ix;
        lblText.Text =ix+" %";
    }

我编写了一个程序，通过读取一个包含大约 1000 个 URL 的文件来下载页面源代码。所以我使用任务来异步下载页面。这里的 Worker.progress 是当前执行的 URL 数量。尽管调试器点击了 backgroundWorker1.ReportProgress(currentProgress);，但它从未进入 backgroundWorker1_ProgressChanged。

 private void StartButton_Click(object sender, EventArgs e)
    {            
        t.makeUrlList(inputFile);

        backgroundWorker1 = new BackgroundWorker();
        backgroundWorker1.WorkerReportsProgress = true;
        backgroundWorker1.DoWork += backgroundWorker1_DoWork;
        backgroundWorker1.ProgressChanged += backgroundWorker1_ProgressChanged;
        backgroundWorker1.RunWorkerAsync();
        t.RunTasks();
        Application.Exit();
    }

后台 worker 在点击开始按钮时初始化...

这里是我创建任务的地方....

public void RunTasks()
    {
        if (numOfTasks > UrlList.Count)
            numOfTasks=UrlList.Count-1;
       Task[] t = new Task[numOfTasks];
        int j = 0;
        while ( j < UrlList.Count-1)
        {

           for (int i = 0; (i < t.Count())&&(j<UrlList.Count-1); i++)
            {


                try
                {
                    if (t[i].IsCompleted || t[i].IsCanceled || t[i].IsFaulted)
                    {
                        t[i] = Task.Run(() => FindWIN(j));
                        j++;
                        progress = j;                            
                    }
                }
                catch (NullReferenceException ex)
                {
                    t[i] = Task.Run(() => FindWIN(j));
                    j++;
                    progress = j;
                }
                }
            }
        }

Answer 1

如果想让BackgroundWorker支持更新进度信息，WorkerReportsProgress的值应该设置为true。如果此属性为 true ，则用户代码可以调用 ReportProgress 以启动事件 ProgressChanged 。

后台 worker 初始化:-

 backgroundWorker1 = new BackgroundWorker();
 backgroundWorker1.WorkerReportsProgress = true;
 backgroundWorker1.DoWork+=backgroundWorker1_DoWork;
 backgroundWorker1.ProgressChanged+=backgroundWorker1_ProgressChanged;
 backgroundWorker1.RunWorkerAsync();

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
            int currentProgress = -1;

            decimal length=1000;
            while (currentProgress < length)
            {
                currentProgress = Worker.progress;
                backgroundWorker1.ReportProgress(currentProgress);
                Thread.Sleep(500);
                length = Worker.UrlList.Count;
            }
 }

private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)        {
            int ix = e.ProgressPercentage;
            progressBar1.Value = ix;
            lblText.Text = ix + " %";
}