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copied!<h3>Older solution, not feasible for tasks that are not cancellation-aware</h3> <p>You should pass a <code>CancellationToken</code>:</p> <pre><code>private async Task DownloadFile() { WebClient client = new WebClient(); using(var cts = new CancellationTokenSource(TimeSpan.FromSeconds(60)) { var downloadTask = Task.Run( () => client.DownloadFile("http://www.worldofcats.com/bigkitty.zip", "c:\\cats\\"), cts.Token ); await downloadTask; } } </code></pre> <p>Now when you <code>await DownloadFile()</code> you can wrap it in a <code>try/catch</code> block to catch the <code>TaskCanceledException</code> (or <a href="https://stackoverflow.com/a/13040503/1180426"><code>OperationCanceledException</code></a>):</p> <pre><code>try { await DownloadFile(); } catch(TaskCanceledException) { //Timeout! } </code></pre> <h3>[EDIT]</h3> <p>As was noticed in comments, you can't cancel a task that's not cancellation-aware - somehow I forgot about that (boo!). But no worries, you can fix that by using <a href="http://msdn.microsoft.com/en-US/library/hh193917.aspx" rel="nofollow noreferrer"><code>DownloadFileTaskAsync</code></a> and <a href="http://msdn.microsoft.com/en-US/library/system.net.webclient.cancelasync.aspx" rel="nofollow noreferrer"><code>CancelAsync</code></a>, so you don't even need cancellation token:</p> <pre><code>var downloadTask = client.DownloadFileTaskAsync("http://www.worldofcats.com/bigkitty.zip", "c:\\cats\\"); var timerTask = Task.Delay(TimeSpan.FromSeconds(60)); await Task.WhenAny(downloadTask, timerTask); client.CancelAsync(); // This does nothing if there's no operation in progress, as noted in documentation </code></pre>

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