Question

我正在使用WebClient并同时下载4个文件。文件是并行下载的，我可以在文件夹中看到文件大小的变化。现在我想显示每个文件的进度条。这是我到目前为止所尝试的，但进展并未发生。有人可以帮忙吗

 private void Button_Click(object sender, RoutedEventArgs e)
    {
            System.Net.ServicePointManager.DefaultConnectionLimit = 10;
            List<String> files = new List<String>();
            String localPath = "";
            files.Add(file1);
            files.Add(file2);
            files.Add(file3);
            files.Add(file4);

            foreach (String fi in files)
            {
                localPath = "C:\\Download\\" + fi.Split('/')[5].ToString();
                WebClient client = new WebClient();

                client.DownloadProgressChanged += (sender1, e1) => client_DownloadProgressChanged(sender1, e1, z);

                client.DownloadFileAsync(new Uri(fi), localPath, count);
                count += 1;
            }
     }

void client_DownloadProgressChanged(object sender, DownloadProgressChangedEventArgs e, int RowNumber)
        {
            ProgressBar[] pb = new ProgressBar[4];

            pb[RowNumber-1] = new ProgressBar();
            pb[RowNumber-1].Width = 400;
            pb[RowNumber-1].Height =20;
            pnl.Children.Add(pb[RowNumber-1]);
            pb[RowNumber-1].Value = e.ProgressPercentage;
        }

Answer 1

这里有多个选项。最好的解决方案是

在DownloadProgressChangedEventHandler方法中为每个文件名使用其他参数。了解如何执行此操作here
使用不同的DownloadProgressChangedEventHandler
许多其他选项，即Parallel.ForEach

第一个解决方案代码（未经过测试 - 我现在无法访问IDE）

List<String> files = new List<String>();
List<ProgressBar> pbs = new List<ProgressBar>();

private void Button_Click(object sender, RoutedEventArgs e)
{
    System.Net.ServicePointManager.DefaultConnectionLimit = 10; 
    String localPath = "";
    files.Add(file1);
    files.Add(file2);
    files.Add(file3);
    files.Add(file4);   

    foreach (String fi in files)
    {
        ProgressBar pb = new ProgressBar();
        pb.Width = 400;
        pb.Height =20;
        pnl.Children.Add(pb);
        pbs.add(pb);

        localPath = "C:\\Download\\" + fi.Split('/')[5].ToString();
        WebClient client = new WebClient();

        client.DownloadProgressChanged += (sender1, e1) => client_DownloadProgressChanged(sender1, e1, fi);

        client.DownloadFileAsync(new Uri(fi), localPath, count);
        count += 1;
    }
}


void client_DownloadProgressChanged(object sender, DownloadProgressChangedEventArgs e, string fi)
{       
    int pbNumber = files.IndexOf(fi);           
    pbs[pbNumber].Value = e.ProgressPercentage;
}

如何显示并行下载的各个ProgressBar？

1 个答案: