Question

我想在我的下载器中实现下载速率。谷歌搜索后发现了一个相当复杂的应用Download manager - limit download speed。然后，在另一个线程https://stackoverflow.com/questions/26073779/how-to-add-download-rate-and-limit-rate-in-downloader-in-c-sharp找到了一个很好的建议：

设置一个每秒触发的计时器，并使用计数器记录已下载的字节数，在计时器Tick事件中将下载速率报告为x Bytes / s，同时将计数器重置为零

使用

开始实现此功能

bytesIn = int.Parse(e.BytesReceived.ToString());
totalBytes = int.Parse(e.TotalBytesToReceive.ToString());

我的代码中有bytesIn显示已接收到的字节但是如何使用定时器实现上面引用的建议，就好像我使用tick()事件并在每个tick（）事件上计算它不会告诉我我的速度。

建议吗？

Answer 1

您需要做的是在计时器中记录bytesIn并存储以供日后使用。下次计时器触发（一秒钟后），您将获取新的bytesIn值，然后减去之前的值。这将获得在最后一秒下载的字节数。您可以在屏幕上将此数字显示为#### Bytes/s，您也可以将该数字除以1024，并将结果显示为#### Kbytes/s。

long lastDownload = 0;
long bytesIn = 0

//This is a event for a timer that fires once per second on the UI thread.
private void TimerTick(object sender, EventArgs e)
{
     //Figure out how many bytes where downloaded in the last second.
     var bytesDownloadedLastSecond = bytesIn - lastsDownload;

     //Copy the number over for the next firing of TimerTick.
     lastDownload = bytesIn;


     double scalingFactor;    
     string formatText;

     //Figure out if we should display in bytes, kilobytes or megabytes per second.
     if(bytesDownloadedLastSecond < 1024)
     {
          formatText = "{0:N0} B/sec";
          scalingFactor = 1;
     }
     else if(bytesDownloadedLastSecond < 1024 * 1024)
     {
          formatText = "{0:N2} Kb/sec";
          scalingFactor = 1024;
     }
     else
     {
          formatText = "{0:N2} Mb/sec";
          scalingFactor = 1024 * 1024;
     }

     //Display the speed to the user, scaled to the correct size.
     speedTextBox.Text = String.Format(formatText, bytesDownloadedLastSecond / scalingFactor );
}

private void DownloadProgress(object sender, EventArgs e)
{
    bytesIn = int.Parse(e.BytesReceived.ToString());
    totalBytes = int.Parse(e.TotalBytesToReceive.ToString());
}

使用C＃下载器的下载速率

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