c# - 如何在 asp.net mvc 中使用 DownloadProgressChangedEventHandler？

Question

我有一个网站，我想用 WebClient 类下载文件。

例如我有我想下载它的网址。在控制台应用程序中，此方法和代码可以正常工作。

这是控制台应用程序中的示例代码:

public void DownloadFile(string sourceUrl, string targetFolder)
    {
        WebClient downloader = new WebClient();
        downloader.Headers.Add("User-Agent", "Mozilla/4.0 (compatible; MSIE 8.0)");
        downloader.DownloadFileCompleted += new AsyncCompletedEventHandler(Downloader_DownloadFileCompleted);
        downloader.DownloadProgressChanged +=
            new DownloadProgressChangedEventHandler(Downloader_DownloadProgressChanged);
        downloader.DownloadFileAsync(new Uri(sourceUrl.Replace(@"\","")), targetFolder);
        while (downloader.IsBusy) { }
    }

private void Downloader_DownloadProgressChanged(object sender, DownloadProgressChangedEventArgs e)
    {
        //Console.Write(e.BytesReceived + " " + e.ProgressPercentage);  

        Console.Write("%" + e.ProgressPercentage);
    }

此示例代码在控制台应用程序中正常工作。

我如何在 asp.net mvc 应用程序中使用此示例代码。

对于 asp.net mvc 它应该是这样的(我认为)

      public ActionResult DownloadPage()
    {
        string url = "https://rjmediamusic.com/media/mp3/mp3-256/Mostafa-Yeganeh-Jadeh.mp3";
        var downld = new DownloadManager();
        downld.DownloadFile(url, @"c:\\temp\1.mp3");
        return View();
    }

对我来说，事件处理程序方法(Downloader_DownloadProgressChanged)非常重要，因为我想在客户端创建进度条。

因为我认为这是做到这一点的最佳方式。但是怎么可能呢？

Answer 1

您可以通过将此代码添加到您的项目来实现此目的:

public void DownloadFile(string sourceUrl, string targetFolder)
{
    WebClient downloader = new WebClient();
    downloader.Headers.Add("User-Agent", "Mozilla/4.0 (compatible; MSIE 8.0)");
downloader.DownloadFileCompleted += new AsyncCompletedEventHandler(Downloader_DownloadFileCompleted);
downloader.DownloadProgressChanged +=
    new DownloadProgressChangedEventHandler(Downloader_DownloadProgressChanged);    
downloader.DownloadFileCompleted += new AsyncCompletedEventHandler(Downloader_DownloadFileCompleted);
    downloader.DownloadProgressChanged +=
        new DownloadProgressChangedEventHandler(Downloader_DownloadProgressChanged);
    downloader.DownloadFileAsync(new Uri(sourceUrl.Replace(@"\","")), targetFolder);
    while (downloader.IsBusy) { }
}

private void Downloader_DownloadProgressChanged(object sender, DownloadProgressChangedEventArgs e)
{
    //Console.Write(e.BytesReceived + " " + e.ProgressPercentage);  

    Console.Write("%" + e.ProgressPercentage);
}