private void convertToPdfButton_Click(object sender, EventArgs e)
{
    // Create a HTML to PDF converter object with default settings
    HtmlToPdfConverter htmlToPdfConverter = new HtmlToPdfConverter();

    // Set license key received after purchase to use the converter in licensed mode
    // Leave it not set to use the converter in demo mode
    htmlToPdfConverter.LicenseKey = "fvDh8eDx4fHg4P/h8eLg/+Dj/+jo6Og=";

    // Add custom HTTP headers

    if (header1NameTextBox.Text.Length > 0 && header1ValueTextBox.Text.Length > 0)
        htmlToPdfConverter.HttpRequestHeaders.Add(header1NameTextBox.Text, header1ValueTextBox.Text);

    if (header2NameTextBox.Text.Length > 0 && header2ValueTextBox.Text.Length > 0)
        htmlToPdfConverter.HttpRequestHeaders.Add(header2NameTextBox.Text, header2ValueTextBox.Text);

    if (header3NameTextBox.Text.Length > 0 && header3ValueTextBox.Text.Length > 0)
        htmlToPdfConverter.HttpRequestHeaders.Add(header3NameTextBox.Text, header3ValueTextBox.Text);

    if (header4NameTextBox.Text.Length > 0 && header4ValueTextBox.Text.Length > 0)
        htmlToPdfConverter.HttpRequestHeaders.Add(header4NameTextBox.Text, header4ValueTextBox.Text);

    if (header5NameTextBox.Text.Length > 0 && header5ValueTextBox.Text.Length > 0)
        htmlToPdfConverter.HttpRequestHeaders.Add(header5NameTextBox.Text, header5ValueTextBox.Text);
            
    Cursor = Cursors.WaitCursor;

    // Convert HTML to PDF using the settings above
    string outPdfFile = @"DemoAppFiles\Output\HTML_to_PDF\HTTP_Headers.pdf";
    try
    {
        // Convert the HTML page to a PDF document in a memory buffer
        byte[] outPdfBuffer = htmlToPdfConverter.ConvertUrl(urlTextBox.Text);

        // Write the memory buffer in a PDF file
        System.IO.File.WriteAllBytes(outPdfFile, outPdfBuffer);
    }
    catch (Exception ex)
    {
        // The HTML to PDF conversion failed
        MessageBox.Show(String.Format("HTML to PDF Error. {0}", ex.Message));
        return;
    }
    finally
    {
        Cursor = Cursors.Arrow;
    }

    // Open the created PDF document in default PDF viewer
    try
    {
        System.Diagnostics.Process.Start(outPdfFile);
    }
    catch (Exception ex)
    {
        MessageBox.Show(String.Format("Cannot open created PDF file '{0}'. {1}", outPdfFile, ex.Message));
    }
}