Print pdf files

Hi,
is it possible to send pdf files directly to the printer without showing any dialog boxes??

I tried this piece of code but it doesn't seem to work...nothing happens..

  Dim startInfo As ProcessStartInfo = New ProcessStartInfo
                startInfo.FileName = row.Cells("File").Value
                startInfo.Verb = "printto"
                startInfo.Arguments = My.Settings.PrinterName
                startInfo.CreateNoWindow = True
                startInfo.WindowStyle = ProcessWindowStyle.Hidden
                startInfo.UseShellExecute = True
                startInfo.ErrorDialog = True
                System.Diagnostics.Process.Start(startInfo)

any ideas??
thanks!