HOWTO: Set Duplex Printing for Word Automation

Microsoft Word for Windows does not provide a method for Automation clients to set the duplex print flag before starting a print job. Although there is a parameter in the PrintOut method that indicates support for duplex printing, the parameter does not provide true duplex printing and may not be available depending on your operating system or installed language. However, developers can work around this limitation on Windows systems by changing the duplex flag for the active printer driver before calling Word's PrintOut function.

This article demonstrates how to use the Windows API to change the duplex setting of the active printer and allow a Word document to be printed in duplex.

This code uses the DocumentProperties API to change the print settings of the printer driver to enable duplex printing. For this code to work successfully, the end user will need adequate permissions to change the global print settings for the printer. If a user does not have the proper permission to change driver settings, they will get an Access Denied error on the OpenPrinter API call.

For users of Microsoft Windows NT and Microsoft Windows 2000 who need to print to a shared network printer, this can be a problem because the print driver does not reside on the local machine but on the print server. Although it is possible for an administrator to configure the print server to give end users the proper permission to change global settings, it is NOT desirable to do so in most cases. To work around this problem, it is possible to install a local print driver for the network printer, and let each user control the settings for their local systems.

Steps to Add Local Print Driver for Network Printer on Windows NT and Windows 2000

1. One the Start menu, select Settings, then select Printers and double-click Add Printer to bring up the Add Printer wizard.
2. When prompted, select printer from "My Computer" and NOT from the network. Although you will connect to a network printer, you want to use a driver on My Computer. Press Next to continue.
3. Click on "Add Port."
4. Select Local Port in the drop-down list box and then click New Port.
5. Type the location of the printer on the network. For example:

       \\printserver\printername (using the exact path name to the printer)
   					

6. Select OK and continue with the rest of the setup.

Changing the printer properties for the active printer will affect all applications that use that printer, and not just Word. If you plan on changing the setting for a particular print job, make sure you restore the setting when the job is complete.

Steps to Build the Sample

1. Open Visual Basic and create a new project. Form1 is created by default.
2. Add a standard BAS module to the project and add the following code to the module's code window:

     
    Option Explicit
   
      Public Type PRINTER_DEFAULTS
   
          pDatatype As Long
          pDevmode As Long
          DesiredAccess As Long
      End Type
   
      Public Type PRINTER_INFO_2
          pServerName As Long
          pPrinterName As Long
          pShareName As Long
          pPortName As Long
          pDriverName As Long
          pComment As Long
          pLocation As Long
          pDevmode As Long       ' Pointer to DEVMODE
          pSepFile As Long
          pPrintProcessor As Long
          pDatatype As Long
          pParameters As Long
          pSecurityDescriptor As Long  ' Pointer to SECURITY_DESCRIPTOR
          Attributes As Long
   
   
          Priority As Long
          DefaultPriority As Long
          StartTime As Long
          UntilTime As Long
          Status As Long
          cJobs As Long
          AveragePPM As Long
      End Type
   
      Public Type DEVMODE
          dmDeviceName As String * 32
   
          dmSpecVersion As Integer
          dmDriverVersion As Integer
          dmSize As Integer
          dmDriverExtra As Integer
          dmFields As Long
          dmOrientation As Integer
          dmPaperSize As Integer
          dmPaperLength As Integer
          dmPaperWidth As Integer
          dmScale As Integer
          dmCopies As Integer
          dmDefaultSource As Integer
          dmPrintQuality As Integer
          dmColor As Integer
          dmDuplex As Integer
          dmYResolution As Integer
          dmTTOption As Integer
          dmCollate As Integer
          dmFormName As String * 32
          dmUnusedPadding As Integer
          dmBitsPerPel As Integer
          dmPelsWidth As Long
          dmPelsHeight As Long
          dmDisplayFlags As Long
          dmDisplayFrequency As Long
          dmICMMethod As Long
          dmICMIntent As Long
          dmMediaType As Long
          dmDitherType As Long
          dmReserved1 As Long
          dmReserved2 As Long
      End Type
   
      Public Const DM_DUPLEX = &H1000&
      Public Const DM_IN_BUFFER = 8
   
      Public Const DM_OUT_BUFFER = 2
      Public Const PRINTER_ACCESS_ADMINISTER = &H4
      Public Const PRINTER_ACCESS_USE = &H8
      Public Const STANDARD_RIGHTS_REQUIRED = &HF0000
      Public Const PRINTER_ALL_ACCESS = (STANDARD_RIGHTS_REQUIRED Or _
                PRINTER_ACCESS_ADMINISTER Or PRINTER_ACCESS_USE)
   
      Public Declare Function ClosePrinter Lib "winspool.drv" _
       (ByVal hPrinter As Long) As Long
      Public Declare Function DocumentProperties Lib "winspool.drv" _
        Alias "DocumentPropertiesA" (ByVal hwnd As Long, _
        ByVal hPrinter As Long, ByVal pDeviceName As String, _
        ByVal pDevModeOutput As Long, ByVal pDevModeInput As Long, _
        ByVal fMode As Long) As Long
      Public Declare Function GetPrinter Lib "winspool.drv" Alias _
        "GetPrinterA" (ByVal hPrinter As Long, ByVal Level As Long, _
        pPrinter As Byte, ByVal cbBuf As Long, pcbNeeded As Long) As Long
      Public Declare Function OpenPrinter Lib "winspool.drv" Alias _
        "OpenPrinterA" (ByVal pPrinterName As String, phPrinter As Long, _
        pDefault As PRINTER_DEFAULTS) As Long
      Public Declare Function SetPrinter Lib "winspool.drv" Alias _
        "SetPrinterA" (ByVal hPrinter As Long, ByVal Level As Long, _
        pPrinter As Byte, ByVal Command As Long) As Long
   
      Public Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" _
       (pDest As Any, pSource As Any, ByVal cbLength As Long)
    
      ' ==================================================================
      ' SetPrinterDuplex 
      '
      '  Programmatically set the Duplex flag for the specified printer
      '  driver's default properties.
      '
      '  Returns: True on success, False on error. (An error will also
   
      '  display a message box. This is done for informational value
      '  only. You should modify the code to support better error
      '  handling in your production application.)
      '
      '  Parameters:
      '    sPrinterName - The name of the printer to be used.
      '
      '    nDuplexSetting - One of the following standard settings:
      '       1 = None
      '       2 = Duplex on long edge (book)
      '       3 = Duplex on short edge (legal)
      '
      ' ==================================================================
      Public Function SetPrinterDuplex(ByVal sPrinterName As String, _
   
          ByVal nDuplexSetting As Long) As Boolean
   
         Dim hPrinter As Long
         Dim pd As PRINTER_DEFAULTS
         Dim pinfo As PRINTER_INFO_2
         Dim dm As DEVMODE
      
         Dim yDevModeData() As Byte
         Dim yPInfoMemory() As Byte
         Dim nBytesNeeded As Long
         Dim nRet As Long, nJunk As Long
      
         On Error GoTo cleanup
      
         If (nDuplexSetting < 1) Or (nDuplexSetting > 3) Then
            MsgBox "Error: dwDuplexSetting is incorrect."
            Exit Function
         End If
         
         pd.DesiredAccess = PRINTER_ALL_ACCESS
         nRet = OpenPrinter(sPrinterName, hPrinter, pd)
         If (nRet = 0) Or (hPrinter = 0) Then
            If Err.LastDllError = 5 Then
               MsgBox "Access denied -- See the article for more info."
            Else
               MsgBox "Cannot open the printer specified " & _
                 "(make sure the printer name is correct)."
            End If
            Exit Function
         End If
      
         nRet = DocumentProperties(0, hPrinter, sPrinterName, 0, 0, 0)
         If (nRet < 0) Then
            MsgBox "Cannot get the size of the DEVMODE structure."
            GoTo cleanup
         End If
      
         ReDim yDevModeData(nRet + 100) As Byte
         nRet = DocumentProperties(0, hPrinter, sPrinterName, _
                     VarPtr(yDevModeData(0)), 0, DM_OUT_BUFFER)
         If (nRet < 0) Then
            MsgBox "Cannot get the DEVMODE structure."
            GoTo cleanup
         End If
      
         Call CopyMemory(dm, yDevModeData(0), Len(dm))
      
         If Not CBool(dm.dmFields And DM_DUPLEX) Then
           MsgBox "You cannot modify the duplex flag for this printer " & _
                  "because it does not support duplex or the driver " & _
                  "does not support setting it from the Windows API."
            GoTo cleanup
         End If
      
         dm.dmDuplex = nDuplexSetting
         Call CopyMemory(yDevModeData(0), dm, Len(dm))
      
         nRet = DocumentProperties(0, hPrinter, sPrinterName, _
           VarPtr(yDevModeData(0)), VarPtr(yDevModeData(0)), _
           DM_IN_BUFFER Or DM_OUT_BUFFER)
   
         If (nRet < 0) Then
           MsgBox "Unable to set duplex setting to this printer."
           GoTo cleanup
         End If
      
         Call GetPrinter(hPrinter, 2, 0, 0, nBytesNeeded)
         If (nBytesNeeded = 0) Then GoTo cleanup
      
         ReDim yPInfoMemory(nBytesNeeded + 100) As Byte
   
         nRet = GetPrinter(hPrinter, 2, yPInfoMemory(0), nBytesNeeded, nJunk)
         If (nRet = 0) Then
            MsgBox "Unable to get shared printer settings."
            GoTo cleanup
         End If
      
         Call CopyMemory(pinfo, yPInfoMemory(0), Len(pinfo))
         pinfo.pDevmode = VarPtr(yDevModeData(0))
         pinfo.pSecurityDescriptor = 0
         Call CopyMemory(yPInfoMemory(0), pinfo, Len(pinfo))
      
         nRet = SetPrinter(hPrinter, 2, yPInfoMemory(0), 0)
         If (nRet = 0) Then
            MsgBox "Unable to set shared printer settings."
         End If
      
         SetPrinterDuplex = CBool(nRet)
   
      cleanup:
         If (hPrinter <> 0) Then Call ClosePrinter(hPrinter)
   
      End Function
   
   
   					

3. On Form1, add a standard Command Button.
4. Add the following code to the code window for Form1:

      Option Explicit
      
      Private Sub Command1_Click()
         Dim oWord As Object
         Dim oDoc As Object
         
         Set oWord = CreateObject("Word.application")
   
         oWord.Visible = True
         
         Set oDoc = oWord.Documents.Add
         oDoc.Range.Select
         
   
         oWord.Selection.TypeText "This is on page 1" & vbCr
         oWord.Selection.InsertBreak 1
         oWord.Selection.TypeText "This is page 2"
         
         SetPrinterDuplex Printer.DeviceName, 2
         
         oDoc.PrintOut Background:=False
         
         SetPrinterDuplex Printer.DeviceName, 1
         
         MsgBox "Print Done", vbMsgBoxSetForeground
         
         oDoc.Saved = True
         oDoc.Close
         Set oDoc = Nothing
      
         oWord.Quit
         Set oWord = Nothing
      End Sub
   
   					

5. Run the sample. If you have a printer that supports duplex printing, the test document should print on both sides of the page.

For more information on problems you might see while trying to print Word documents using a duplex printer, please see the following articles in the Microsoft Knowledge Base: