How can I scrape web pages in parallel using C#?

I'm trying to scrape some Web pages after the Javascript code has been executed. I need to do that in parallel because I have to scrape over 500 pages.

So far I tried on this way:

This is the class used to Scrape

 public class Class1
{
    private HtmlAgilityPack.HtmlDocument Doc;
    private string page1;
    private string page2;
    private string page3;

    public async Task<string> LoadDynamicPage(string url, CancellationToken token, WebBrowser webBrowser)
    {
        // navigate and await DocumentCompleted
        var tcs = new TaskCompletionSource<bool>();
        WebBrowserDocumentCompletedEventHandler handler = (s, arg) =>
            tcs.TrySetResult(true);

        using (token.Register(() => tcs.TrySetCanceled(), useSynchronizationContext: true))
        {

            webBrowser.DocumentCompleted += handler;

            try
            {

                webBrowser.Navigate(url);

                await tcs.Task; // wait for DocumentCompleted
            }
            finally
            {

                webBrowser.DocumentCompleted -= handler;

            }
        }

        // get the root element

        var documentElement = webBrowser.Document.GetElementsByTagName("html")[0];



        // poll the current HTML for changes asynchronosly
        var html = documentElement.OuterHtml;
        while (true)
        {
            // wait asynchronously, this will throw if cancellation requested
            await Task.Delay(500, token);

            // continue polling if the WebBrowser is still busy
            if (webBrowser.IsBusy)
                continue;

            var htmlNow = documentElement.OuterHtml;
            if (html == htmlNow)
                break; // no changes detected, end the poll loop

            html = htmlNow;
        }

        // consider the page fully rendered 
        token.ThrowIfCancellationRequested();
        return html;
    }

    private async Task InitializeHTML(string html, WebBrowser webBrowser)
    {
        var cts = new CancellationTokenSource(TimeSpan.FromSeconds(3600));
        string code = await LoadDynamicPage(html, cts.Token, webBrowser);

        Doc = new HtmlAgilityPack.HtmlDocument();
        Doc.LoadHtml(code);
    }

    public async Task<Class1> GetData(string standardPage, WebBrowser webBrowser)
    {
        Class1 obj = new Class1();

        try
        {
            // Navigate to standardPage
            await InitializeHTML(standardPage, webBrowser);

            // ---
            // Do some operations 
            // ---

            // Navigate to page1
            await InitializeHTML(page1, webBrowser);

            // ---
            // Do some operations 
            // ---

            // Navigate to page2
            await InitializeHTML(page2, webBrowser);

            // ---
            // Do some operations 
            // ---

            // Navigate to page3
            await InitializeHTML(page3, webBrowser);

            // ---
            // Do some operations 
            // ---

        }
        catch (Exception exc)
        {
            Debug.WriteLine(exc.Message);
        }

        return obj;
    }
}

So on LoadDynamicPage function, I use a Web Browser to get the HTML code after the Javascript has been executed.

Then InitializeHTML is used to create a HTML Document with HtmlAgilityPack.

Finally I have the Scrape Method (GetData) where I scrape several subpages of the website passed as parameter and it returns a Class1 object asynchronously.

Here I call the GetData function:

 public class Class2
{

    public async void DoWork()
    {
        // Web Pages List
        List<string> pages = new List<string> {"www.example.com", "www.example2.com" };

        WebBrowser webBrowser = new WebBrowser();

        List<Task<Class1>> tasks = new List<Task<Class1>>();

        // Class1 Objects List to be filled with Task results
        List<Class1> objects = new List<Class1>();

        // Temp object to access Class1.GetData Method
        Class1 tmpObj = new Class1();

        for (int i = 0; i < pages.Count; i++)
        {
            tasks.Add(tmpObj.GetData(pages[i], webBrowser));
        }

        var results = await Task.WhenAll(tasks.ToArray());

    }
}

There are no errors but I get always the same HTML code (same web page) on the Task results at the end.

Where did I go wrong?

Thanks for the help.