calculate sending file speed/sec in less than a second (without using thread.sleep)

Question

This is a file transfer (Server-Client tcp sockets)

The code below shows the transfer rate per second (kb/s) every one second.

I want to show the the speed (rate/s) every time I send the data to the client. How do I calculate the speed every time (without usings thread.sleep(1000))?

private void timeElasped()
    {
        int rate = 0;
        int prevSent = 0;
        while (fileTransfer.busy)
        {
            rate = fileTransfer.Sent - prevSent ;
            prevSum = fileTransfer.Sent;
            RateLabel(string.Format("{0}/Sec", CnvrtUnit(rate)));
            if(rate!=0)
                Timeleft = (fileTransfer.fileSize - fileTransfer.sum) / rate;
            TimeSpan t = TimeSpan.FromSeconds(Timeleft);
            timeLeftLabel(FormatRemainingText(rate, t));
            Thread.Sleep(1000);
        }
    }

Answer 1

in form constructor

Timer timer1 = new Time();
public Form1()
{
    InitializeComponent();
    this.timer1.Enabled = true;
    this.timer1.Interval = 1000;
    this.timer1.Tick += new System.EventHandler(this.timer1_Tick);
}

or add it from toolbox and set the previous values

the sum of sent bytes should be public so our method can get its value every second

long sentBytes = 0;      //the sent bytes that updated from sending method
long prevSentBytes = 0;   //which references to the previous sentByte
double totalSeconds = 0;   //seconds counter to show total time .. it increases everytime the timer1 ticks.
private void timer1_Tick(object sender, EventArgs e)
{
    long speed = sentBytes - prevSentBytes ;  //here's the Transfer-Rate or Speed
    prevSentBytes = sentBytes ;
    labelSpeed.Text = CnvrtUnit(speed) + "/S";   //display the speed like (100 kb/s) to a label
    if (speed > 0)                //considering that the speed would be 0 sometimes.. we avoid dividing on 0 exception
    {
        totalSeconds++;     //increasing total-time
        labelTime.Text = TimeToText(TimeSpan.FromSeconds((sizeAll - sumAll) / speed));
        //displaying time-left in label
        labelTotalTime.Text = TimeToText(TimeSpan.FromSeconds(totalSeconds));
        //displaying total-time in label
    }
}

private string TimeToText(TimeSpan t)
{
    return string.Format("{2:D2}:{1:D2}:{0:D2}", t.Seconds, t.Minutes, t.Hours);
}

private string CnvrtUnit(long source)
{
    const int byteConversion = 1024;
    double bytes = Convert.ToDouble(source);

    if (bytes >= Math.Pow(byteConversion, 3)) //GB Range
    {
        return string.Concat(Math.Round(bytes / Math.Pow(byteConversion, 3), 2), " GB");
    }
    else if (bytes >= Math.Pow(byteConversion, 2)) //MB Range
    {
        return string.Concat(Math.Round(bytes / Math.Pow(byteConversion, 2), 2), " MB");
    }
    else if (bytes >= byteConversion) //KB Range
    {
        return string.Concat(Math.Round(bytes / byteConversion, 2), " KB");
    }
    else //Bytes
    {
        return string.Concat(bytes, " Bytes");
    }
}