ASP.NET MVC example of using ABCpdf to convert HTML to PDF

ABCpdfUtils.cs

public static byte[] PDFForHtml(string html)
{
    // Create ABCpdf Doc object
    var doc = new Doc();

    // Add html to Doc
    int theID = doc.AddImageHtml(html);

    // Loop through document to create multi-page PDF
    while (true)
    {
        if (!doc.Chainable(theID))
            break;
        doc.Page = doc.AddPage();
        theID = doc.AddImageToChain(theID);
    }

    // Flatten the PDF
    for (int i = 1; i <= doc.PageCount; i++)
    {
        doc.PageNumber = i;
        doc.Flatten();
    }

    // Get PDF as byte array. Couls also use .Save() to save to disk
    var pdfbytes = doc.GetData();

    doc.Clear();

    return pdfbytes;
}

MVCHelpers.cs

public static string RenderViewToString(Controller controller, string viewName, object model, string masterName)
{
    controller.ViewData.Model = model;

    using (StringWriter sw = new StringWriter())
    {
        ViewEngineResult viewResult = ViewEngines.Engines.FindView(controller.ControllerContext, viewName, masterName);
        ViewContext viewContext = new ViewContext(controller.ControllerContext, viewResult.View, controller.ViewData, controller.TempData, sw);
        viewResult.View.Render(viewContext, sw);

        return sw.GetStringBuilder().ToString();
    }
}

ReportsController.cs

public ActionResult Projections(ProjectionsReportViewModel model)
{
    // Return view if there is an error
    if (!ModelState.IsValid)
    {
        return View(model);
    }

    // If user has clicked the export button
    if (model.Export)
    {
        // Render view output to string
        var report = RenderViewToString(this, "Projections", model, "_Print");

        // Convert string to PDF using ABCpdf
        var pdfbytes = PDFForHtml(report);

        // Return file result
        return File(pdfbytes, System.Net.Mime.MediaTypeNames.Application.Pdf, "Report.pdf");
    }

    // Not exporting to PDF, show the view
    return View(model);
}

It returns the pdf, only it is empty, despite pdfbytes is not empty! any suggestions?
tried with stream also

Solved :P
Why i need to clear the doc after i already got the bytes? how can that affect the pdfbytes variable?