Private Sub convertToPdfButton_Click(ByVal sender As Object, ByVal e As EventArgs) Handles convertToPdfButton.Click ' Create a PDF document Dim pdfDocument As New Document() ' Set license key received after purchase to use the converter in licensed mode ' Leave it not set to use the converter in demo mode pdfDocument.LicenseKey = "fvDh8eDx4fHg4P/h8eLg/+Dj/+jo6Og=" ' Add a page to PDF document Dim pdfPage As PdfPage = pdfDocument.AddPage() Cursor = Cursors.WaitCursor Dim outPdfFile As String = "DemoAppFiles\Output\PDF_Creator\Digital_Signatures.pdf" Try Dim htmlWithDigitalSignatureMarker As String = htmlStringTextBox.Text Dim baseUrl As String = baseUrlTextBox.Text ' Add a HTML string with a marker for digital signature to PDF document Dim htmlToPdfElement As New HtmlToPdfElement(htmlWithDigitalSignatureMarker, baseUrl) pdfPage.AddElement(htmlToPdfElement) ' Make the HTML element with 'digital_signature_element' mapping ID a link to digital signature properties Dim digitalSignatureMapping As HtmlElementMapping = htmlToPdfElement.HtmlElementsMappingOptions.HtmlElementsMappingResult.GetElementByMappingId("digital_signature_element") If digitalSignatureMapping IsNot Nothing Then Dim digitalSignaturePage As PdfPage = digitalSignatureMapping.PdfRectangles(0).PdfPage Dim digitalSignatureRectangle As RectangleF = digitalSignatureMapping.PdfRectangles(0).Rectangle Dim certificateFilePath As String = "DemoAppFiles\Input\Certificates\wnvpdf.pfx" ' Get the certificate from password protected PFX file Dim certificates As DigitalCertificatesCollection = DigitalCertificatesStore.GetCertificates(certificateFilePath, "wnvpdf") Dim certificate As DigitalCertificate = certificates(0) ' Create the digital signature Dim signature As New DigitalSignatureElement(digitalSignatureRectangle, certificate) signature.Reason = "Protect the document from unwanted changes" signature.ContactInfo = "The contact email is support@winnovative-software.com" signature.Location = "Development server" digitalSignaturePage.AddElement(signature) End If ' Save the PDF document in a memory buffer Dim outPdfBuffer() As Byte = pdfDocument.Save() ' Write the memory buffer in a PDF file System.IO.File.WriteAllBytes(outPdfFile, outPdfBuffer) Catch ex As Exception ' The PDF creation failed MessageBox.Show(String.Format("Create PDF Document Error. {0}", ex.Message)) Return Finally ' Close the PDF document pdfDocument.Close() Cursor = Cursors.Arrow End Try ' Open the created PDF document in default PDF viewer Try 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