Using BackgroundWorker with Progressbar in WindowsForm with different Classes

Question

I have 2 different classes downloadWiki and GetLinks, each one has a loop that needs a bit time to execute, and a Form.cs class where my buttons and progress bar are.

My downloadWiki has a loop that loops through different html pages, and the GetLinks class has a loop that gets every link on each Wiki page and sends it to my downloadWiki class. After some if statements I download some of those wikis. Now my problem, I tried the last 2 hours to implement a progress bar and backgroundworker for the loop with the links and for the one which downloads the wikipages. But I didn't found a solution. This is the code I execute in my Windows Forms code. So I don't know how to send a backgroundWorker to those two classes.

Please comment if you need more Code.

Sorry if this is easy to google question, but I'm a "newbie" in C#

    private void button1_Click(object sender, EventArgs e)
    {
        DownloadWikis wikis = new DownloadWikis();
    }

Answer 1

First, you need to configure your backgroundworker:

    public FrmMain()
    {
        InitializeComponent();

        _backgroundWorker.WorkerReportsProgress = true;
        _backgroundWorker.ProgressChanged += _backgroundWorker_ProgressChanged;
        _backgroundWorker.DoWork += _backgroundWorker_DoWork;
        _backgroundWorker.RunWorkerCompleted += _backgroundWorker_RunWorkerCompleted;
    }

You want a progressBar, so your backgroundWorker needs to report progress. The work will be done asynchronously, so you need to specify a delegate where your download will be executed.

    private void _backgroundWorker_DoWork(object sender, DoWorkEventArgs e)
    {
        DownloadWikis wikis = new DownloadWikis();

    }

In your DownloadWikis class, write a delegate. It will help us to call the backgroundworker ReportProgress method.

     public delegate void ReportProgressDelegate(int percentage);

Update your Download signature, it should be like this:

    public void Download(ReportProgressDelegate reportProgress)
    {
        // FirstLoop
        for(int i=0; i < 100; i++)
        {
            // Do some work with GetLinks
            // this will call the backgroundworker ReportProgress method.
            reportProgress(i);
        }
    }

Now, you can complete with this:

    private void _backgroundWorker_DoWork(object sender, DoWorkEventArgs e)
    {
        DownloadWikis wiki = new DownloadWikis();
        wiki.Download(_backgroundWorker.ReportProgress);
    }

To handle the progress bar value, the second delegate is here:

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

With this step, you will be able to see when your work will be completed:

     private void _backgroundWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {
        MessageBox.Show("It's done !");
    }

Last step, the easy one:

    private void btnDownloadWikis_Click(object sender, EventArgs e)
    {
        _backgroundWorker.RunWorkerAsync();
    }

Now, you have to do some maths do determine your percentage.