下载时C＃进度栏不会更新

Question

I am downloading a file from ftp server with a BackgroundWorker but the progress only updates when the file is already finished downloading.

Progress bar stays at 0, freezes for the duration of download, and sets to 100.

Here's my code:

    private void backgroundWorker1_DoWork(object sender, System.ComponentModel.DoWorkEventArgs e) {
        FtpWebRequest request = (FtpWebRequest)WebRequest.Create(activeDownload.ftpPath);
        request.Credentials = new NetworkCredential(ftpUser, ftpPass);
        request.Method = WebRequestMethods.Ftp.DownloadFile;

        FtpWebResponse response = (FtpWebResponse)request.GetResponse();
        Stream responseStream = response.GetResponseStream();

        using (FileStream writer = new FileStream(activeDownload.localPath, FileMode.Create)) {

            long length = response.ContentLength;
            int bufferSize = 2048;
            int readCount;
            byte[] buffer = new byte[2048];
            long bytesread = 0;
            backgroundWorker1.ReportProgress(0);

            readCount = responseStream.Read(buffer, 0, bufferSize);
            while (readCount > 0) {
                bytesread += readCount;
                writer.Write(buffer, 0, readCount);
                backgroundWorker1.ReportProgress((int)(bytesread / activeDownload.fileSize) * 100);
                readCount = responseStream.Read(buffer, 0, bufferSize);
            }
        }

        response.Close();
        responseStream.Close();
    }

    private void backgroundWorker1_ProgressChanged(object sender, System.ComponentModel.ProgressChangedEventArgs e) {
        progressBar1.Value = e.ProgressPercentage;
    }

What am I doing wrong? Any help would be appreciated.

Answer 1

Set the value, then run below

progressbar1.PerformStep()

You can also do

progressBar1.Refresh()

Answer 2

see if the following links helps:

From Stack and MSDN

Below is sample code what I have implemented in one of my projects:

public ProcessFilesClass()
    {
        InitializeComponent();
        backgroundWorker1= new BackgroundWorker();
        backgroundWorker1.DoWork += new DoWorkEventHandler(backgroundWorker1_DoWork);
        backgroundWorker1.RunWorkerCompleted += new RunWorkerCompletedEventHandler(backgroundWorker1_RunWorkerCompleted);
        backgroundWorker1.ProgressChanged += new ProgressChangedEventHandler(backgroundWorker1_ProgressChanged);
    }

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
    {
        BackgroundWorker worker = sender as BackgroundWorker;
        var backgroundWorker = sender as BackgroundWorker;
        worker.WorkerReportsProgress = true;
        WorkerProcessMethod();
    }

private void WorkerProcessMethod()
    {
            //Process items in list box
            int itemsToProcess = someListBox.Items.Count;
            for (int i = 0; i < itemsToProcess; i++)
                {
                    int findPercentage = ((i + 1) * 100) / someListBox.Items.Count;
                     if (backgroundWorker1 != null) { backgroundWorker1.ReportProgress(findPercentage, null); }
                }
    }

private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
    {
           progressBar1.Value = e.ProgressPercentage;

    }

private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {
          //DisableProgressBarStatus
           this.Close();            
    }

Answer 3

Ok so it turned out that I was doing everything fine but I was parsing the percentage wrong. Dividing two longs (bytesread and activeDownload.fileSize) was returning 0. Hence, the progress was stuck at 0%.

Here is the correct parsing:

backgroundWorker1.ReportProgress(Convert.ToInt32((((double)bytesread / activeDownload.fileSize) * 100)));