如果文件超过500mb，DownloadFileAsync应用程序没有响应？

Question

so I'm using webClient.DownloadFileAsync(url, sFilePathToWriteFileTo); to download a file

Url is string url = "http://localhost/1.zip";

sFilePathToWriteFileTo is root directory

Whenever I download the 500mb zip archive, my label1 goes berserk and says "Downloading with INF kb/s" and that's about when it starts not responding and crashes

label1 is label1.Text = string.Format("Downloading with {0} kb/s", (e.BytesReceived / 1024d / sw.Elapsed.TotalSeconds).ToString("0.00"));

It works perfectly fine when I'm downloading low size files, 20mb-50mb

Oh btw, (I just re-read my post), sw is StopWatch, incase you wonder

What is the problem here, and how can I solve it?

-- Edit, added webClient:

using (webClient = new WebClient())
                {
                    webClient.DownloadFileCompleted += new AsyncCompletedEventHandler(wzCompleted);
                    webClient.DownloadProgressChanged += new DownloadProgressChangedEventHandler(wzProgressChanged);
                    Uri url = new Uri(sUrlToReadFileFrom);
                    sw.Start();
                    try
                    {
                        webClient.DownloadFileAsync(url, sFilePathToWriteFileTo);
                    }
                    catch (Exception ex)
                    {
                        downloadInfo.Text = ex.Message;
                    }
                }

wzProgressChanged:

private void wzProgressChanged(object sender, DownloadProgressChangedEventArgs e)
    {
        statusContent.Text = "Downloading new game files";
        downloadInfo.Text = "Downloading: " + string.Format("{0} MB / {1} MB", (e.BytesReceived / 1024d / 1024d).ToString("0.00"), (e.TotalBytesToReceive / 1024d / 1024d).ToString("0.00")) + " with " + string.Format("{0} kb/s", (e.BytesReceived / 1024d / sw.Elapsed.TotalSeconds).ToString("0.00")) + " (" + e.ProgressPercentage.ToString() + "%" + ")";
        progressBar1.Value = e.ProgressPercentage;
    }

wzCompleted: It's just enabling 2 buttons and disabling 2 others, no need for this?

Answer 1

Do 3 things in your wzProgressChanged handler:

1. Make sure you marshal the control updates onto the UI thread (assuming it's WinForms use InvokeRequired and Invoke )
2. Make sure sw.Elapsed.TotalSeconds isn't zero to avoid divide by zero
3. Wrap the whole body of the handler in a try catch so you can see exceptions your code may be throwing.

Read the documentation about InvokeRequired. It will tell you all about the UI thread and how to make sure you are updating the UI appropriately. I would make the code look something like this (not tested or even compiled but is pretty close)

private void wzProgressChanged(object sender, DownloadProgressChangedEventArgs e)
{
    if (this.InvokeRequired)
    {
        this.Invoke(() => wzProgressChanged(sender, e));
    }
    else if (sw.Elapsed.TotalSeconds > 0)
    {
        try
        {
            statusContent.Text = "Downloading new game files";
            downloadInfo.Text = "Downloading: " + string.Format("{0} MB / {1} MB", (e.BytesReceived / 1024d / 1024d).ToString("0.00"), (e.TotalBytesToReceive / 1024d / 1024d).ToString("0.00")) + " with " + string.Format("{0} kb/s", (e.BytesReceived / 1024d / sw.Elapsed.TotalSeconds).ToString("0.00")) + " (" + e.ProgressPercentage.ToString() + "%" + ")";
            progressBar1.Value = e.ProgressPercentage;
        }
        catch(Exception e)
        {
            System.Diagnostics.Debug.WriteLine(e.Message);
        }
    }
}

Answer 2

In addition to what dkackman suggested, I'd also suggest being a bit more selective about how often you update your label and maybe put some additional checking around your values to ensure you don't get values line NaN/INF. See other posts here on SO around what they mean exactly. Look at methods like Double.IsInfinity to help you determine if your calc resulted in a number that can be displayed or not.

Also, do some of your calculations outside of your string format statement and based on your findings, you could decide what information to provide to the user.