    using System;
    using System.Collections.Generic;
    using System.Web;
    using System.Web.UI;
    using System.Web.UI.WebControls;

    using System.Drawing;

    // Use EVO PDF Namespace
    using EvoPdfClient;

    namespace EvoHtmlToPdfDemo.HTML_to_PDF.PDF_Security
    {
        public partial class Digital_Signatures : System.Web.UI.Page
        {
            protected void convertToPdfButton_Click(object sender, EventArgs e)
            {
                // Get the server IP and port
                String serverIP = textBoxServerIP.Text;
                uint serverPort = uint.Parse(textBoxServerPort.Text);

                // Create a HTML to PDF converter object
                HtmlToPdfConverter htmlToPdfConverter = null;
                if (radioButtonUseTcpService.Checked)
                    htmlToPdfConverter = new HtmlToPdfConverter(serverIP, serverPort);
                else
                    htmlToPdfConverter = new HtmlToPdfConverter(true, textBoxWebServiceUrl.Text);

                // Set optional service password
                if (textBoxServicePassword.Text.Length > 0)
                    htmlToPdfConverter.ServicePassword = textBoxServicePassword.Text;

                // 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 = "4W9+bn19bn5ue2B+bn1/YH98YHd3d3c=";

                // 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;

                string htmlWithDigitalSignatureMarker = htmlStringTextBox.Text;
                string baseUrl = baseUrlTextBox.Text;

                // Convert a HTML string with a marker for digital signature to a PDF document object
                Document pdfDocument = htmlToPdfConverter.ConvertHtmlToPdfDocumentObject(htmlWithDigitalSignatureMarker, baseUrl);

                // Make the HTML element with 'digital_signature_element' mapping ID a link to digital signature properties
                HtmlElementMapping digitalSignatureMapping = htmlToPdfConverter.HtmlElementsMappingOptions.HtmlElementsMappingResult.GetElementByMappingId("digital_signature_element");
                if (digitalSignatureMapping != null)
                {
                    PdfPage digitalSignaturePage = pdfDocument.GetPage(digitalSignatureMapping.PdfRectangles[0].PageIndex);
                    RectangleFloat digitalSignatureRectangle = digitalSignatureMapping.PdfRectangles[0].Rectangle;

                    string certificateFilePath = Server.MapPath("~/DemoAppFiles/Input/Certificates/evopdf.pfx");

                    // Create the digital signature
                    DigitalSignatureElement signature = new DigitalSignatureElement(digitalSignatureRectangle, certificateFilePath, "evopdf", 0);
                    signature.Reason = "Protect the document from unwanted changes";
                    signature.ContactInfo = "The contact email is support@evopdf.com";
                    signature.Location = "Development server";
                    digitalSignaturePage.AddElement(signature);
                }

                // Save the PDF document in a memory buffer
                byte[] outPdfBuffer = pdfDocument.Save();

                // Send the PDF as response to browser

                // Set response content type
                Response.AddHeader("Content-Type", "application/pdf");

                // Instruct the browser to open the PDF file as an attachment or inline
                Response.AddHeader("Content-Disposition", String.Format("attachment; filename=Digital_Signatures.pdf; size={0}", outPdfBuffer.Length.ToString()));

                // Write the PDF document buffer to HTTP response
                Response.BinaryWrite(outPdfBuffer);

                // End the HTTP response and stop the current page processing
                Response.End();
            }

            protected void Page_Load(object sender, EventArgs e)
            {
                if (!IsPostBack)
                {
                    string currentPageUrl = HttpContext.Current.Request.Url.AbsoluteUri;
                    string rootUrl = "http://www.evopdf.com/demo/";

                    htmlStringTextBox.Text = System.IO.File.ReadAllText(Server.MapPath("~/DemoAppFiles/Input/HTML_Files/Digital_Signatures.html"));
                    baseUrlTextBox.Text = rootUrl + "DemoAppFiles/Input/HTML_Files/";

                    sampleCodeLiteral.Text = System.IO.File.ReadAllText(Server.MapPath("~/DemoAppFiles/Input/Code_Samples/CSharp/AspNet/HTML_to_PDF/PDF_Security/Digital_Signatures.html"));
                    descriptionLiteral.Text = System.IO.File.ReadAllText(Server.MapPath("~/DemoAppFiles/Input/Descriptions/AspNet/HTML_to_PDF/PDF_Security/Digital_Signatures.html"));

                    Master.CollapseAll();
                    Master.ExpandNode("HTML_to_PDF");
                    Master.ExpandNode("PDF_Security_Features");
                    Master.SelectNode("Digital_Signatures");
                }
            }

            protected void demoMenu_MenuItemClick(object sender, MenuEventArgs e)
            {
                switch (e.Item.Value)
                {
                    case "Live_Demo":
                        demoMultiView.SetActiveView(liveDemoView);
                        break;
                    case "Description":
                        demoMultiView.SetActiveView(descriptionView);
                        break;
                    case "Sample_Code":
                        demoMultiView.SetActiveView(sampleCodeView);
                        break;
                    default:
                        break;
                }
            }
        }
    }