Q266767: HOWTO: Set Which Printer Is the System Default Printer
Article: Q266767
Product(s): Microsoft Visual Basic for Windows
Version(s): 4.0,5.0,6.0
Operating System(s):
Keyword(s): kbprint kbAPI kbGDI kbPrinting kbSDKWin32 kbSpooler kbVBp kbVBp400 kbVBp500 kbVBp600 kb
Last Modified: 04-FEB-2002
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The information in this article applies to:
- Microsoft Visual Basic Professional Edition for Windows, versions 4.0, 5.0, 6.0
- Microsoft Visual Basic Enterprise Edition for Windows, versions 4.0, 5.0, 6.0
- Microsoft Visual Basic Learning Edition for Windows, versions 5.0, 6.0
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SUMMARY
=======
This article shows how to programmatically set which printer is the system
default printer. Not all applications or components can select a specific
printer to use. This often makes it necessary to change the default printer for
the system so that the application or component will use the desired printer.
MORE INFORMATION
================
NOTE: This code changes the default printer for the entire system. So all
applications that do not specify a printer, even applications that are currently
running, use this same default. For this reason, you may want to have your code
remember the previous default and then set it back when your print job is
finished.
The following code sample provides a means to determine which printers are
available, and to designate one as the system default printer.
Step-by-Step Example
--------------------
1. Start a new Standard EXE project in Visual Basic. Form1 is created by
default.
2. Add a new module to the project and insert the following code:
Public Const HWND_BROADCAST = &HFFFF
Public Const WM_WININICHANGE = &H1A
' constants for DEVMODE structure
Public Const CCHDEVICENAME = 32
Public Const CCHFORMNAME = 32
' constants for DesiredAccess member of PRINTER_DEFAULTS
Public Const STANDARD_RIGHTS_REQUIRED = &HF0000
Public Const PRINTER_ACCESS_ADMINISTER = &H4
Public Const PRINTER_ACCESS_USE = &H8
Public Const PRINTER_ALL_ACCESS = (STANDARD_RIGHTS_REQUIRED Or _
PRINTER_ACCESS_ADMINISTER Or PRINTER_ACCESS_USE)
' constant that goes into PRINTER_INFO_5 Attributes member
' to set it as default
Public Const PRINTER_ATTRIBUTE_DEFAULT = 4
' Constant for OSVERSIONINFO.dwPlatformId
Public Const VER_PLATFORM_WIN32_WINDOWS = 1
Public Type OSVERSIONINFO
dwOSVersionInfoSize As Long
dwMajorVersion As Long
dwMinorVersion As Long
dwBuildNumber As Long
dwPlatformId As Long
szCSDVersion As String * 128
End Type
Public Type DEVMODE
dmDeviceName As String * CCHDEVICENAME
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 * CCHFORMNAME
dmLogPixels As Integer
dmBitsPerPel As Long
dmPelsWidth As Long
dmPelsHeight As Long
dmDisplayFlags As Long
dmDisplayFrequency As Long
dmICMMethod As Long ' // Windows 95 only
dmICMIntent As Long ' // Windows 95 only
dmMediaType As Long ' // Windows 95 only
dmDitherType As Long ' // Windows 95 only
dmReserved1 As Long ' // Windows 95 only
dmReserved2 As Long ' // Windows 95 only
End Type
Public Type PRINTER_INFO_5
pPrinterName As String
pPortName As String
Attributes As Long
DeviceNotSelectedTimeout As Long
TransmissionRetryTimeout As Long
End Type
Public Type PRINTER_DEFAULTS
pDatatype As Long
pDevMode As Long
DesiredAccess As Long
End Type
Declare Function GetProfileString Lib "kernel32" _
Alias "GetProfileStringA" _
(ByVal lpAppName As String, _
ByVal lpKeyName As String, _
ByVal lpDefault As String, _
ByVal lpReturnedString As String, _
ByVal nSize As Long) As Long
Declare Function WriteProfileString Lib "kernel32" _
Alias "WriteProfileStringA" _
(ByVal lpszSection As String, _
ByVal lpszKeyName As String, _
ByVal lpszString As String) As Long
Declare Function SendMessage Lib "user32" _
Alias "SendMessageA" _
(ByVal hwnd As Long, _
ByVal wMsg As Long, _
ByVal wParam As Long, _
lparam As String) As Long
Declare Function GetVersionExA Lib "kernel32" _
(lpVersionInformation As OSVERSIONINFO) As Integer
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 Any, _
ByVal Command As Long) As Long
Public Declare Function GetPrinter Lib "winspool.drv" _
Alias "GetPrinterA" _
(ByVal hPrinter As Long, _
ByVal Level As Long, _
pPrinter As Any, _
ByVal cbBuf As Long, _
pcbNeeded As Long) As Long
Public Declare Function lstrcpy Lib "kernel32" _
Alias "lstrcpyA" _
(ByVal lpString1 As String, _
ByVal lpString2 As Any) As Long
Public Declare Function ClosePrinter Lib "winspool.drv" _
(ByVal hPrinter As Long) As Long
Public Sub SelectPrinter(NewPrinter As String)
Dim Prt As Printer
For Each Prt In Printers
If Prt.DeviceName = NewPrinter Then
Set Printer = Prt
Exit For
End If
Next
End Sub
3. Place a ListBox and a CommandButton on Form1.
4. Add the following code to the General Declarations section of Form1:
Option Explicit
Private Function PtrCtoVbString(Add As Long) As String
Dim sTemp As String * 512, x As Long
x = lstrcpy(sTemp, Add)
If (InStr(1, sTemp, Chr(0)) = 0) Then
PtrCtoVbString = ""
Else
PtrCtoVbString = Left(sTemp, InStr(1, sTemp, Chr(0)) - 1)
End If
End Function
Private Sub SetDefaultPrinter(ByVal PrinterName As String, _
ByVal DriverName As String, ByVal PrinterPort As String)
Dim DeviceLine As String
Dim r As Long
Dim l As Long
DeviceLine = PrinterName & "," & DriverName & "," & PrinterPort
' Store the new printer information in the [WINDOWS] section of
' the WIN.INI file for the DEVICE= item
r = WriteProfileString("windows", "Device", DeviceLine)
' Cause all applications to reload the INI file:
l = SendMessage(HWND_BROADCAST, WM_WININICHANGE, 0, "windows")
End Sub
Private Sub Win95SetDefaultPrinter()
Dim Handle As Long 'handle to printer
Dim PrinterName As String
Dim pd As PRINTER_DEFAULTS
Dim x As Long
Dim need As Long ' bytes needed
Dim pi5 As PRINTER_INFO_5 ' your PRINTER_INFO structure
Dim LastError As Long
' determine which printer was selected
PrinterName = List1.List(List1.ListIndex)
' none - exit
If PrinterName = "" Then
Exit Sub
End If
' set the PRINTER_DEFAULTS members
pd.pDatatype = 0&
pd.DesiredAccess = PRINTER_ALL_ACCESS Or pd.DesiredAccess
' Get a handle to the printer
x = OpenPrinter(PrinterName, Handle, pd)
' failed the open
If x = False Then
'error handler code goes here
Exit Sub
End If
' Make an initial call to GetPrinter, requesting Level 5
' (PRINTER_INFO_5) information, to determine how many bytes
' you need
x = GetPrinter(Handle, 5, ByVal 0&, 0, need)
' don't want to check Err.LastDllError here - it's supposed
' to fail
' with a 122 - ERROR_INSUFFICIENT_BUFFER
' redim t as large as you need
ReDim t((need \ 4)) As Long
' and call GetPrinter for keepers this time
x = GetPrinter(Handle, 5, t(0), need, need)
' failed the GetPrinter
If x = False Then
'error handler code goes here
Exit Sub
End If
' set the members of the pi5 structure for use with SetPrinter.
' PtrCtoVbString copies the memory pointed at by the two string
' pointers contained in the t() array into a Visual Basic string.
' The other three elements are just DWORDS (long integers) and
' don't require any conversion
pi5.pPrinterName = PtrCtoVbString(t(0))
pi5.pPortName = PtrCtoVbString(t(1))
pi5.Attributes = t(2)
pi5.DeviceNotSelectedTimeout = t(3)
pi5.TransmissionRetryTimeout = t(4)
' this is the critical flag that makes it the default printer
pi5.Attributes = PRINTER_ATTRIBUTE_DEFAULT
' call SetPrinter to set it
X = SetPrinter(Handle, 5, pi5, 0)
If X = False Then ' SetPrinter failed
MsgBox "SetPrinter Failed. Error code: " & Err.LastDllError
Exit Sub
Else
If Printer.DeviceName <> List1.Text Then
' Make sure Printer object is set to the new printer
SelectPrinter (List1.Text)
End If
End If
' and close the handle
ClosePrinter (Handle)
End Sub
Private Sub GetDriverAndPort(ByVal Buffer As String, DriverName As _
String, PrinterPort As String)
Dim iDriver As Integer
Dim iPort As Integer
DriverName = ""
PrinterPort = ""
' The driver name is first in the string terminated by a comma
iDriver = InStr(Buffer, ",")
If iDriver > 0 Then
' Strip out the driver name
DriverName = Left(Buffer, iDriver - 1)
' The port name is the second entry after the driver name
' separated by commas.
iPort = InStr(iDriver + 1, Buffer, ",")
If iPort > 0 Then
' Strip out the port name
PrinterPort = Mid(Buffer, iDriver + 1, _
iPort - iDriver - 1)
End If
End If
End Sub
Private Sub ParseList(lstCtl As Control, ByVal Buffer As String)
Dim i As Integer
Dim s As String
Do
i = InStr(Buffer, Chr(0))
If i > 0 Then
s = Left(Buffer, i - 1)
If Len(Trim(s)) Then lstCtl.AddItem s
Buffer = Mid(Buffer, i + 1)
Else
If Len(Trim(Buffer)) Then lstCtl.AddItem Buffer
Buffer = ""
End If
Loop While i > 0
End Sub
Private Sub WinNTSetDefaultPrinter()
Dim Buffer As String
Dim DeviceName As String
Dim DriverName As String
Dim PrinterPort As String
Dim PrinterName As String
Dim r As Long
If List1.ListIndex > -1 Then
' Get the printer information for the currently selected
' printer in the list. The information is taken from the
' WIN.INI file.
Buffer = Space(1024)
PrinterName = List1.Text
r = GetProfileString("PrinterPorts", PrinterName, "", _
Buffer, Len(Buffer))
' Parse the driver name and port name out of the buffer
GetDriverAndPort Buffer, DriverName, PrinterPort
If DriverName <> "" And PrinterPort <> "" Then
SetDefaultPrinter List1.Text, DriverName, PrinterPort
If Printer.DeviceName <> List1.Text Then
' Make sure Printer object is set to the new printer
SelectPrinter (List1.Text)
End If
End If
End Sub
Private Sub Command1_Click()
Dim osinfo As OSVERSIONINFO
Dim retvalue As Integer
osinfo.dwOSVersionInfoSize = 148
osinfo.szCSDVersion = Space$(128)
retvalue = GetVersionExA(osinfo)
If osinfo.dwPlatformId = VER_PLATFORM_WIN32_WINDOWS Then
Call Win95SetDefaultPrinter
Else
' This assumes that future versions of Windows use the NT method
Call WinNTSetDefaultPrinter
End If
End Sub
Private Sub Form_Load()
Dim r As Long
Dim Buffer As String
' Get the list of available printers from WIN.INI
Buffer = Space(8192)
r = GetProfileString("PrinterPorts", vbNullString, "", _
Buffer, Len(Buffer))
' Display the list of printer in the ListBox List1
ParseList List1, Buffer
End Sub
5. Run the project and note that the preceding code populates a ListBox with all
available printers.
6. Select one printer in the list and make it the default by clicking the
CommandButton.
7. Confirm that the default printer has changed: On the Start button, select
Settings, select Printers, and then check which printer is marked as the
default. Alternatively, you can print to the default printer from any
application on your system.
REFERENCES
==========
For additional information, click the article numbers below to view the articles
in the Microsoft Knowledge Base:
Q167735 FIX: Setting Printer to Item in the Printers Collection Fails
Q253612 FIX: Printers Collection May Not Contain All Printers in the Printers
Folder
Q246772 HOWTO: Retrieve and Set the Default Printer in Windows
Additional query words: global
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Keywords : kbprint kbAPI kbGDI kbPrinting kbSDKWin32 kbSpooler kbVBp kbVBp400 kbVBp500 kbVBp600 kbGrpDSVB kbDSupport kbCodeSnippet
Technology : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB500Search kbVB600Search kbVB500 kbVB600 kbVB400Search kbVB400
Version : :4.0,5.0,6.0
Issue type : kbhowto
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