如何使用webclient下載檔案，使用memortstream將它們保存為gif型別影像，同時還報告進度？

private async Task DownloadAsync()
        {
            using (var client = new WebClient())
            {
                client.DownloadFileCompleted  = (s, e) =>
                {
                    if (e.Error == null)
                    {
                        urlsCounter--;

                        var t = urls;

                        if (urlsCounter == 0)
                        {
                            CheckIfImagesExist();

                            btnRadarPath.Enabled = true;
                            btnSatellitePath.Enabled = true;

                            radCounter = 0;
                            satCounter = 0;

                            lblStatus.Text = "Completed.";

                            dates = rad.dates;
                            var images = System.IO.Directory.GetFiles(radarFolderImagesDownload,
                                  "*.gif", SearchOption.AllDirectories).OrderBy(x => x).ToArray();

                            Array.Sort(images, new MyComparer(false));

                            if (images.Length > 0)
                            {
                                for (int i = 0; i < images.Length; i  )
                                {
                                    drawOnImage.DrawText(dates[i].ToString("ddd, dd MMM yyy HH':'mm"), images[i]);
                                }
                            }

                            GetImagesFiles();
                        }
                    }
                    else
                    {
                        string error = e.Error.ToString();
                    }
                };

                client.DownloadProgressChanged  = (s, e) => tracker.SetProgress(e.BytesReceived, e.TotalBytesToReceive);
                client.DownloadProgressChanged  = (s, e) => lblAmount.Text = tracker.SizeSuffix(e.BytesReceived)   "/"   tracker.SizeSuffix(e.TotalBytesToReceive);
                client.DownloadProgressChanged  = (s, e) => lblSpeed.Text = tracker.GetBytesPerSecondString();
                client.DownloadProgressChanged  = (s, e) => myLong = Convert.ToInt64(client.ResponseHeaders["Content-Length"]);
                client.DownloadProgressChanged  = (s, e) =>
                {
                    progressBar1.Value = e.ProgressPercentage;
                    label1.Text = e.ProgressPercentage   "%";
                };

                for (int i = 0; i < urls.Count; i  )
                {
                    tracker.NewFile();

                    if (urls[i].Contains("Radar"))
                    {
                        await client.DownloadFileTaskAsync(new Uri(urls[i]), radarFolderImagesDownload   "\\image"   radCounter   ".gif");

                        radCounter  ;
                    }
                    else
                    {
                        using (MemoryStream ms = new MemoryStream(client.DownloadData(new Uri(urls[i]))))
                        {
                            Image img = Image.FromStream(ms, true);
                            img.Save(satelliteFolderImagesDownload   "\\image"   satCounter   ".gif", System.Drawing.Imaging.ImageFormat.Gif);
                        }

                        satCounter  ;
                    }
                }
            }
        }

它下載一切正常，但是當它下載衛星影像部分時：

using (MemoryStream ms = new MemoryStream(client.DownloadData(new Uri(urls[i]))))
                            {
                                Image img = Image.FromStream(ms, true);
                                img.Save(satelliteFolderImagesDownload   "\\image"   satCounter   ".gif", System.Drawing.Imaging.ImageFormat.Gif);
                            }
    
                            satCounter  ;

它不像以前那樣報告進度。

在我以前下載與雷達部分相同的影像之前：

await Client.DownloadFileTaskAsync(new Uri(urls[i]), fNameSat);

但是因為我想在下載衛星影像時將衛星影像保存為 gif，所以我現在正在使用 memorystream 和 image.save，這可以避免它向 progressBar 和所有其他 client.DownloadProgressChanged event/s 報告進度

我怎樣才能讓它使用記憶體流并將它們保存為 gif 并繼續報告進度？

uj5u.com熱心網友回復：

嘗試這個：

List<string> Urls = new List<string>();

Urls.Add("a url");
Urls.Add("another url");

for(int i = 0; i < Urls.Count; i  )
{
   System.Net.WebClient WC = new System.Net.WebClient();

   WC.DownloadFileAsync(new Uri(Urls[i]), @"The location you want to save the file...");
   WC.DownloadFileCompleted  = (s, e) =>
   {
      progressBar1.Value  = progressBar1.Maximum / Urls.Count;
   };
}

這將下載串列中的所有 url。

標籤：C＃ winforms

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