Private Sub convertToPdfButton_Click(sender As Object, e As EventArgs) Handles convertToPdfButton.Click
    ' Create a HTML to PDF converter object with default settings
    Dim htmlToPdfConverter As 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="

    ' Set an adddional delay in seconds to wait for JavaScript or AJAX calls after page load completed
    ' Set this property to 0 if you don't need to wait for such asynchcronous operations to finish
    htmlToPdfConverter.ConversionDelay = 2

    ' Set the PDF file to be inserted before the table of contents
    htmlToPdfConverter.PdfDocumentOptions.AddStartDocument(pdfBeforeTextBox.Text)

    ' Enable the creation of a table of contents from H1 to H6 tags found in HTML
    htmlToPdfConverter.TableOfContentsOptions.AutoTocItemsEnabled = autoTableOfContentsCheckBox.Checked

    ' Optionally set the table of contents title
    htmlToPdfConverter.TableOfContentsOptions.Title = "Table of Contents"

    ' Optionally set the title style using CSS sttributes
    htmlToPdfConverter.TableOfContentsOptions.TitleStyle = "color:navy; font-family:'Times New Roman'; font-size:28px; font-weight:normal"

    ' Optionally set the style of level 1 items in table of contents
    Dim level1TextStyle As String = "color:black; font-family:'Times New Roman'; font-size:20px; font-weight:normal; font-style:normal; background-color:#F0F0F0"
    htmlToPdfConverter.TableOfContentsOptions.SetItemStyle(1, level1TextStyle)

    ' Optionally set the page numbers style of level 1 items in table of contents
    Dim level1PageNumberStyle As String = "color:black; padding-right:3px; background-color:#F0F0F0; font-size:14px; font-weight:bold"
    htmlToPdfConverter.TableOfContentsOptions.SetPageNumberStyle(1, level1PageNumberStyle)

    Cursor = Cursors.WaitCursor

    ' Convert HTML to PDF using the settings above
    Dim outPdfFile As String = "DemoAppFiles\Output\HTML_to_PDF\Insert_PDF_Before_Table_of_Contents.pdf"
    Try
        ' Convert the HTML page to a PDF document in a memory buffer
        Dim outPdfBuffer As Byte() = htmlToPdfConverter.ConvertUrl(urlTextBox.Text)

        ' Write the memory buffer in a PDF file
        System.IO.File.WriteAllBytes(outPdfFile, outPdfBuffer)
    Catch ex As Exception
        ' The HTML to PDF conversion failed
        MessageBox.Show(String.Format("HTML to PDF Error. {0}", ex.Message))
        Return
    Finally
        Cursor = Cursors.Arrow
    End Try

    ' Open the created PDF document in default PDF viewer
    Try
        System.Diagnostics.Process.Start(outPdfFile)
    Catch ex As Exception
        MessageBox.Show(String.Format("Cannot open created PDF file '{0}'. {1}", outPdfFile, ex.Message))
    End Try
End Sub