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Monitor Printer Queues


Allows you to check the number of waiting print jobs on network printers.

Option Explicit

'Constants Definition
Public Const CCHDEVICENAME = 32
Public Const CCHFORMNAME = 32
Public Const PRINTER_ACCESS_ADMINISTER = &H4
Public Const PRINTER_ACCESS_USE = &H8

'Types Definition
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
    dmUnusedPadding As Integer
    dmBitsPerPel As Long
    dmPelsWidth As Long
    dmPelsHeight As Long
    dmDisplayFlags As Long
    dmDisplayFrequency As Long
End Type

Public Type PRINTER_DEFAULTS
    pDatatype As String
    pDevMode As DEVMODE
    DesiredAccess As Long
End Type

Public Type SYSTEMTIME
    wYear As Integer
    wMonth As Integer
    wDayOfWeek As Integer
    wDay As Integer
    wHour As Integer
    wMinute As Integer
    wSecond As Integer
    wMilliseconds As Integer
End Type

Public Type JOB_INFO_1_API
    JobId As Long
    pPrinterName As Long
    pMachineName As Long
    pUserName As Long
    pDocument As Long
    pDatatype As Long
    pStatus As Long
    Status As Long
    Priority As Long
    Position As Long
    TotalPages As Long
    PagesPrinted As Long
    Submitted As SYSTEMTIME
End Type

Public Type JOB_INFO_1
    JobId As Long
    pPrinterName As String
    pMachineName As String
    pUserName As String
    pDocument As String
    pDatatype As String
    pStatus As String
    Status As Long
    Priority As Long
    Position As Long
    TotalPages As Long
    PagesPrinted As Long
    Submitted As SYSTEMTIME
End Type

'API Declarations
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 EnumJobs Lib "winspool.drv" Alias "EnumJobsA" (ByVal HPrinter As Long, ByVal FirstJob As Long, ByVal NoJobs As Long, ByVal Level As Long, ByVal pJob As Long, ByVal cdBuf As Long, pcbNeeded As Long, pcReturned As Long) As Long
Public Declare Function CloseHandle Lib "kernel32.dll" (ByVal hObject As Long) As Long

Private Declare Sub CopyMem Lib "kernel32.dll" Alias "RtlMoveMemory" (pTo As Any, uFrom As Any, ByVal lSize As Long)
Private Declare Function lstrlenW Lib "kernel32.dll" (ByVal lpString As Long) As Long

Private Declare Function HeapAlloc Lib "kernel32.dll" (ByVal hHeap As Long, ByVal dwFlags As Long, ByVal dwBytes As Long) As Long
Private Declare Function GetProcessHeap Lib "kernel32.dll" () As Long
Private Declare Function HeapFree Lib "kernel32.dll" (ByVal hHeap As Long, ByVal dwFlags As Long, lpMem As Any) As Long

'Public structure filled by GetPrinterQueue with all the documents data in the selected printer queue
Public JobsDesc(0 To 127) As JOB_INFO_1

Public Function TrimStr(strName As String) As String
    'Finds a null then trims the string
    Dim x As Integer

    x = InStr(strName, vbNullChar)
    If x > 0 Then TrimStr = Left(strName, x - 1) Else TrimStr = strName
End Function

Function LPSTRtoSTRING(ByVal lngPointer As Long) As String
    Dim lngLength As Long

    'Get number of characters in string
    lngLength = lstrlenW(lngPointer) * 2
    'Initialize string so we have something to copy the string into
    LPSTRtoSTRING = String(lngLength, 0)
    'Copy the string
    CopyMem ByVal StrPtr(LPSTRtoSTRING), ByVal lngPointer, lngLength
    'Convert to Unicode
    LPSTRtoSTRING = TrimStr(StrConv(LPSTRtoSTRING, vbUnicode))
End Function

'Get the number of Jobs in the specified Printer Queue (max 128)... the PrinterName can be a network path: "\\MYSERVER\MYPRINTER"
Function GetPrinterQueue(PrinterName As String) As Long
    Dim PrinterStruct As PRINTER_DEFAULTS
    Dim HPrinter As Long
    Dim ret As Boolean
    Dim Jobs(0 To 127) As JOB_INFO_1_API
    Dim pcbNeeded As Long
    Dim pcReturned As Long
    Dim i As Integer
    Dim TempBuff As Long

    'Initialize the Printer structure
    PrinterStruct.pDatatype = vbNullString
    PrinterStruct.pDevMode.dmSize = Len(PrinterStruct.pDevMode)
    PrinterStruct.DesiredAccess = PRINTER_ACCESS_USE
    'Get the printer Handle
    ret = OpenPrinter(PrinterName, HPrinter, PrinterStruct)
    'Get the Printer active jobs
    ret = EnumJobs(HPrinter, 0, 127, 1, TempBuff, 0, pcbNeeded, pcReturned)
    If pcbNeeded = 0 Then
        GetPrinterQueue = 0
    Else
        'Allocate the Buffer
        TempBuff = HeapAlloc(GetProcessHeap(), 0, pcbNeeded)
        ret = EnumJobs(HPrinter, 0, 127, 1, TempBuff, pcbNeeded, pcbNeeded, pcReturned)
        CopyMem Jobs(0), ByVal TempBuff, pcbNeeded
        For i = 0 To pcReturned - 1
            JobsDesc(i).pPrinterName = LPSTRtoSTRING(Jobs(i).pPrinterName)
            JobsDesc(i).pMachineName = LPSTRtoSTRING(Jobs(i).pMachineName)
            JobsDesc(i).pUserName = LPSTRtoSTRING(Jobs(i).pUserName)
            JobsDesc(i).pDocument = LPSTRtoSTRING(Jobs(i).pDocument)
            JobsDesc(i).pDatatype = LPSTRtoSTRING(Jobs(i).pDatatype)
            JobsDesc(i).pStatus = LPSTRtoSTRING(Jobs(i).pStatus)
            JobsDesc(i).JobId = Jobs(i).JobId
            JobsDesc(i).Status = Jobs(i).Status
            JobsDesc(i).Priority = Jobs(i).Priority
            JobsDesc(i).Position = Jobs(i).Position
            JobsDesc(i).TotalPages = Jobs(i).TotalPages
            JobsDesc(i).PagesPrinted = Jobs(i).PagesPrinted
            JobsDesc(i).Submitted = Jobs(i).Submitted
        Next
        If TempBuff Then HeapFree GetProcessHeap(), 0, TempBuff
        GetPrinterQueue = pcReturned
    End If
    'Close printer
    ret = CloseHandle(HPrinter)
End Function

Usage

Create a form with a command button.

Private Sub Command1_Click()
    'Get the Default Printer's Queue
    MsgBox "Number of Documents in Queue: " & GetPrinterQueue(Printer.DeviceName)
End Sub

About this post

Posted: 2019-10-07
By: AndreaTincani
Viewed: 343 times

Categories

Visual Basic 6

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Special Instructions

This code originally appeared on AndreaVB.com, and has been republished here with the permission of Andrea Tincani.


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