How to silent print the PDF document from WCF service

  public object CreatePDF()
        {
 
            PdfDocument document = new PdfDocument();
 
            //Add a page to the document
 
            PdfPage page = document.Pages.Add();
 
            //Create PDF graphics for the page
 
            PdfGraphics graphics = page.Graphics;
 
            //Set the standard font
 
            PdfFont font = new PdfStandardFont(PdfFontFamily.Helvetica, 20);
 
            //Draw the text
 
            graphics.DrawString("Hello World!!!", font, PdfBrushes.Black, new PointF(0, 0));
 
            //Save the document
                      
            MemoryStream ms = new MemoryStream();
 
            document.Save(ms);
 
            string base64 = Convert.ToBase64String(ms.ToArray());
          
            return base64;
          
        }        

$.ajax({
            url: "http://localhost:12263/pdfviewer.asmx/CreatePDF",
            type: 'POST',
            crossDomain: true,
            contentType: 'application/json; charset=utf-8',
            dataType: 'json',
            traditional: true,
            success: function (data) {
                var jsonResult = new Object();
                jsonResult["base64"] = data["d"];
                $.ajax({
                    url: "../api/PdfViewer/PdfViewerPrint",
                    type: 'POST',
                    contentType: 'application/json; charset=utf-8',
                    dataType: 'json',
                    data: JSON.stringify(jsonResult),
                    crossDomain: true,
                    traditional: true,
                    success: function () {
                        var div = document.getElementById('result');
                        div.innerHTML += 'PDF document is printed';                       
                    }
                });
            }
        });

public void PdfViewerPrint(Dictionary<string, string> jsonResult)
        {
            //Initializes the PDF viewer      
 
            PdfViewerControl viewer = new PdfViewerControl();
 
            //Loading the document in PDF viewer control
            if (jsonResult.ContainsKey("base64"))
            {
                var data = jsonResult["base64"];
 
                byte[] byteArray = Convert.FromBase64String(data);
 
                MemoryStream stream = new MemoryStream(byteArray);
 
                viewer.Load(stream);
 
                //Initializes the print dialog box
 
                PrintDialog dialog = new PrintDialog();
 
                dialog.AllowPrintToFile = true;
 
                //Sets the PDF viewer print document to PrintDialog's document
 
                dialog.Document = viewer.PrintDocument;
 
                //Prints the PDF document
 
                dialog.Document.Print();
 
            }            
        }