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PODownloadStringAsync multiple URLs maintaining order
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  1. PODownloadStringAsync multiple URLs maintaining order
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    copied!<p>I need to download multiple HTML pages as strings and store them into a list. But then need to be stored in the order i started the downloads. At the moment the list is in the order of download completion. So when a download finishes, its contents gets added to a list. But they dont necessarily finish in the order they were started. And im kinda stumped on how to store this data in a list in the order they were initiated.</p> <p>Here is my current code, this initiates the download sequence. URLList is a list of urls, and i need the downloaded strings to be in the same order as this original list:</p> <pre><code>cts = new CancellationTokenSource(); try { await AccessTheWebAsync(cts.Token); listBox1.DataSource = VideoList; } catch (Exception) { MessageBox.Show("\r\nDownload failed.\r\n"); } cts = null; </code></pre> <p>Then that calls the following code:</p> <pre><code>async Task AccessTheWebAsync(CancellationToken ct) { HttpClient client = new HttpClient(); client.DefaultRequestHeaders.Add("user-agent", "Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.2; WOW64; Trident/6.0)"); IEnumerable&lt;Task&lt;string&gt;&gt; downloadTasksQuery = from url in URLList select ProcessURL(url, client, ct); List&lt;Task&lt;string&gt;&gt; downloadTasks = downloadTasksQuery.ToList(); while (downloadTasks.Count &gt; 0) { Task&lt;string&gt; firstFinishedTask = await Task.WhenAny(downloadTasks); downloadTasks.Remove(firstFinishedTask); string length = await firstFinishedTask; //this is the data of the first finished download int refPoint = length.IndexOf("Download (Save as...): &lt;a href=\"") + 32; VideoList.Add(length.Substring(refPoint, length.IndexOf("\"&gt;", refPoint) - refPoint)); } } async Task&lt;string&gt; ProcessURL(string url, HttpClient client, CancellationToken ct) { HttpResponseMessage response = await client.GetAsync(url, ct); string urlContents = await response.Content.ReadAsStringAsync(); return urlContents; } </code></pre> <p>Im sure its something rather simple. But i just need the downloaded strings to be in the same order as the original URLList list. Any help would be much appreciated.</p>
 

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