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Question:

C# HTTP DownloadAync BytesPerSec

Jan 09 '16 at 07:40

How can I pull the bytes per sec transfer speed when using DownloadAsync? I had iterated through the http eventlog before for "RecvBytesPerSec", but this does not seem to exist in the task ProgressInfo

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Answer

The Async methods should still fire events, so you can get the SendRate/ReceiveRate events, but beware because the events will be called in the background thread. In other words, when your event handler is called, it's in a background thread and you cannot just update a UI element. If you need to update UI elements from the bg thread, use MethodInvoker. See http://www.cknotes.com/vb-net-taskcompleted-event-for-asynchronous-method-call/

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Answer

Hello, Thanks for responding, however I am not seeing any events get invoked.

    public bool Download(string url, string destinationPath, bool unzip)
    {

        _http.KeepEventLog = true;
        _http.EnableEvents = true;
        _http.OnReceiveRate += _http_OnReceiveRate;
        Task task = _http.DownloadAsync(url, destinationPath);
        task.OnProgressInfo += task_OnProgressInfo;
        task.OnPercentDone += task_OnPercentDone;
        task.KeepProgressLog = true;
        task.EnableEvents = true;

        task.Run();

        while (!task.Finished)
        {

            while (task.ProgressLogSize > 0)
            {
                string logName = task.ProgressInfoName(0);
                string logValue = task.ProgressInfoValue(0);
                task.RemoveProgressInfo(0);
                Debug.Print(logName);
                if (logName.Contains("RecvBytesPerSec"))
                {
                    double bytesPerSec;
                    if (double.TryParse(logValue, out bytesPerSec) == false)
                        bytesPerSec = 0;

                    string transferSpeed = ConvertBytesToTransferSpeed(bytesPerSec);
                    Debug.Print("Speed: " + transferSpeed);
                }
                else if (logName.Contains("PercentDone"))
                {
                    double percentDone;
                    if (double.TryParse(logValue, out percentDone) == false)
                        percentDone = 100.0;

                    Debug.Print("Percent: " + percentDone);
                }
            }

            task.SleepMs(100);
        }

        return true;

    }

    void _http_OnReceiveRate(object sender, DataRateEventArgs args)
    {
        Debug.Print(args.BytesPerSec.ToString());
    }

    void task_OnPercentDone(object sender, PercentDoneEventArgs args)
    {
        Debug.Print(args.PercentDone.ToString());
    }

    private void task_OnProgressInfo(object sender, ProgressInfoEventArgs args)
    {
        Debug.Print(args.Name + " " + args.Value);
    }

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Answer

Try registering the event on the http-object instead of the task-object.