在VB中怎样将一台打印机设为默认的打印机?

这是一个从组合框中选择打印机的示例代码：Private Sub Form_Load()  Dim prn As Printer  If Printers.Count > 0 Then
    For Each prn In Printers
        cmbPrinter.AddItem prn.DeviceName
    Next prn
  End IfEnd Sub
Private Sub cmbPrinter_Validate(Cancel As Boolean)    Dim prn As Printer

    If cmbPrinter <> "" Then
        Cancel = True
        For Each prn In Printers
            If cmbPrinter = prn.DeviceName Then
                Cancel = False
                Set Printer = prn
                Exit For
            End If
        Next prn
    End If    If Cancel = True Then
        MsgBox "没有找到此打印机", vbInformation
    End IfEnd Sub

不会吧，我测试中没有出问题的。
你试试在上面的代码中的set printer=prn这句之后，加两句测试：Private Sub cmbPrinter_Validate(Cancel As Boolean)    Dim prn As Printer

    If cmbPrinter <> "" Then
        Cancel = True
        For Each prn In Printers
            If cmbPrinter = prn.DeviceName Then
                Cancel = False
                Set Printer = prn
                printer.print "ABCDE"    '加上这两句立即测试
                printer.enddoc           '如果没问题，那可能是你的其他的地方的代码的干扰。
                Exit For
            End If
        Next prn
    End If    If Cancel = True Then
        MsgBox "没有找到此打印机", vbInformation
    End IfEnd Sub

我是这样做的
‘在注册表中的打印机放在这个位置
NoncePrinter = GetStringValue("HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows NT\Currentversion\Windows", _
        "device")  '检查当前打印机
varr = Split(NoncePrinter, ",")
NoncePrinter = varr(0)
If NoncePrinter <> Printer Then '假如当前打印机与要更改的打印机不同，则更改打印机
        yy = SetValue("HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows 　　　　　　　　　　　　NT\Currentversion\Windows", _
            "device", Printer & ",winspool,Ne02:", "String")
End If
NoncePrinter 是系统当前的打印机
Printer 是要设置的打印机。

If NoncePrinter <> Printer Then
-------------------------------
这里的比较是不是有问题？printer的缺省成员是什么？我不太清楚，不过应该不是devicename吧.

模块：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 = 1Public Type OSVERSIONINFO
    dwOSVersionInfoSize As Long
    dwMajorVersion As Long
    dwMinorVersion As Long
    dwBuildNumber As Long
    dwPlatformId As Long
    szCSDVersion As String * 128
End TypePublic 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 TypePublic Type PRINTER_INFO_5
     pPrinterName As String
     pPortName As String
     Attributes As Long
     DeviceNotSelectedTimeout As Long
     TransmissionRetryTimeout As Long
End TypePublic Type PRINTER_DEFAULTS
     pDatatype As Long
     pDevMode As Long
     DesiredAccess As Long
End TypeDeclare 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 LongDeclare Function WriteProfileString Lib "kernel32" _
Alias "WriteProfileStringA" _
(ByVal lpszSection As String, _
ByVal lpszKeyName As String, _
ByVal lpszString As String) As LongDeclare Function SendMessage Lib "user32" _
Alias "SendMessageA" _
(ByVal hwnd As Long, _
ByVal wMsg As Long, _
ByVal wParam As Long, _
lparam As String) As LongDeclare Function GetVersionExA Lib "kernel32" _
(lpVersionInformation As OSVERSIONINFO) As IntegerPublic Declare Function OpenPrinter Lib "winspool.drv" _
Alias "OpenPrinterA" _
(ByVal pPrinterName As String, _
phPrinter As Long, _
pDefault As PRINTER_DEFAULTS) As LongPublic Declare Function SetPrinter Lib "winspool.drv" _
Alias "SetPrinterA" _
(ByVal hPrinter As Long, _
ByVal Level As Long, _
pPrinter As Any, _
ByVal Command As Long) As LongPublic 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 LongPublic Declare Function lstrcpy Lib "kernel32" _
Alias "lstrcpyA" _
(ByVal lpString1 As String, _
ByVal lpString2 As Any) As LongPublic 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

窗体：Option ExplicitPrivate 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 FunctionPrivate 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 SubPrivate 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 SubPrivate 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 SubPrivate 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 SubPrivate 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 SubPrivate 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 SubPrivate 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

以上代码是设置一台打印机为默认打印机的代码，在窗体上加一个command1和List1

调试易

在VB中怎样将一台打印机设为默认的打印机?

解决方案 »