ACC: Enumerating Local and Network Printers
ID: Q166008
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The information in this article applies to:
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Microsoft Access versions 7.0, 97
SUMMARY
Advanced: Requires expert coding, interoperability, and multiuser skills.
This article shows you two procedures that use the EnumPrinters API
function to retrieve a list of printers available locally and that your
computer is connected to on the network.
The procedures demonstrate returning data to both the PRINTER_INFO_1
structure and the PRINTER_INFO_4 structure, each of which provides slightly
different information about the printer. If you are using Microsoft
Windows 95 or later, you can return data to the PRINTER_INFO_1 structure;
if you are using Microsoft Windows NT, you can return data to either
structure.
This article assumes that you are familiar with Visual Basic for
Applications and with creating Microsoft Access applications using the
programming tools provided with Microsoft Access. For more information
about Visual Basic for Applications, please refer to your version of the
"Building Applications with Microsoft Access" manual.
MORE INFORMATION
WARNING: ANY USE BY YOU OF THE CODE PROVIDED IN THIS ARTICLE IS AT YOUR OWN
RISK. Microsoft provides this code "as is" without warranty of any kind,
either express or implied, including but not limited to the implied
warranties of merchantability and/or fitness for a particular purpose.
Use the Sub routine EnumeratePrinters1 if you are running Microsoft
Windows 95 or later. You can use either Sub routine if you are running
Microsoft Windows NT.
The code in each of the two examples performs these steps:
- Calls the EnumPrinters API, which returns a buffer of data, a success flag, and a flag indicating whether the buffer is too small.
- If the buffer is too small, makes it the correct size and calls the API again.
- For each entry in the buffer, extracts the data and prints it.
NOTE: When using these functions in your own applications, you may want to
return an array of data that can be displayed in a list box or grid rather
than print the values.
The buffer is in the following format:
|rec1|rec2|...|recn|...garbage...|strn|...|str2|str1|
INFO records containing string pointers and numeric values are added from
the left, and the string text for each record is added from the right. The
area between the end of the last record and the start of the last string
text contains garbage.
The buffer is declared as type Long, which makes extracting data from the
records easier - all fields are either Long or pointers (pointers map to
Long).
The StrLen() and PtrToStr() functions are used to set up the receiving
string variable and to copy the text from the buffer to the variable.
- Create a module and type the following lines in the Declarations section:
Option Explicit
Const PRINTER_ENUM_CONNECTIONS = &H4
Const PRINTER_ENUM_LOCAL = &H2
Type PRINTER_INFO_1
flags As Long
pDescription As String
PName As String
PComment As String
End Type
Type PRINTER_INFO_4
pPrinterName As String
pServerName As String
Attributes As Long
End Type
Declare Function EnumPrinters Lib "winspool.drv" Alias _
"EnumPrintersA" (ByVal flags As Long, ByVal name As String, _
ByVal Level As Long, pPrinterEnum As Long, ByVal cdBuf As Long, _
pcbNeeded As Long, pcReturned As Long) As Long
Declare Function PtrToStr Lib "Kernel32" Alias "lstrcpyA" _
(ByVal RetVal As String, ByVal Ptr As Long) As Long
Declare Function StrLen Lib "Kernel32" Alias "lstrlenA" _
(ByVal Ptr As Long) As Long
- Type the following procedures:
Sub EnumeratePrinters1()
Dim Success As Boolean, cbRequired As Long, cbBuffer As Long
Dim Buffer() As Long, nEntries As Long
Dim I As Long, PFlags As Long, PDesc As String, PName As String
Dim PComment As String, Temp As Long
cbBuffer = 3072
ReDim Buffer((cbBuffer \ 4) - 1) As Long
Success = EnumPrinters(PRINTER_ENUM_CONNECTIONS Or _
PRINTER_ENUM_LOCAL, _
vbNullString, _
1, _
Buffer(0), _
cbBuffer, _
cbRequired, _
nEntries)
If Success Then
If cbRequired > cbBuffer Then
cbBuffer = cbRequired
Debug.Print "Buffer too small. Trying again with " & _
cbBuffer & " bytes."
ReDim Buffer(cbBuffer \ 4) As Long
Success = EnumPrinters(PRINTER_ENUM_CONNECTIONS Or _
PRINTER_ENUM_LOCAL, _
vbNullString, _
1, _
Buffer(0), _
cbBuffer, _
cbRequired, _
nEntries)
If Not Success Then
Debug.Print "Error enumerating printers."
Exit Sub
End If
End If
Debug.Print "There are " & nEntries & _
" local and connected printers."
For I = 0 To nEntries - 1
PFlags = Buffer(4 * I)
PDesc = Space$(StrLen(Buffer(I * 4 + 1)))
Temp = PtrToStr(PDesc, Buffer(I * 4 + 1))
PName = Space$(StrLen(Buffer(I * 4 + 2)))
Temp = PtrToStr(PName, Buffer(I * 4 + 2))
PComment = Space$(StrLen(Buffer(I * 4 + 2)))
Temp = PtrToStr(PComment, Buffer(I * 4 + 2))
Debug.Print PFlags, PDesc, PName, PComment
Next I
Else
Debug.Print "Error enumerating printers."
End If
End Sub
Sub EnumeratePrinters4()
Dim Success As Boolean, cbRequired As Long, cbBuffer As Long
Dim Buffer() As Long, nEntries As Long
Dim I As Long, PName As String, SName As String
Dim Attrib As Long, Temp As Long
cbBuffer = 3072
ReDim Buffer((cbBuffer \ 4) - 1) As Long
Success = EnumPrinters(PRINTER_ENUM_CONNECTIONS Or _
PRINTER_ENUM_LOCAL, _
vbNullString, _
4, _
Buffer(0), _
cbBuffer, _
cbRequired, _
nEntries)
If Success Then
If cbRequired > cbBuffer Then
cbBuffer = cbRequired
Debug.Print "Buffer too small. Trying again with " & _
cbBuffer & " bytes."
ReDim Buffer(cbBuffer \ 4) As Long
Success = EnumPrinters(PRINTER_ENUM_CONNECTIONS Or _
PRINTER_ENUM_LOCAL, _
vbNullString, _
4, _
Buffer(0), _
cbBuffer, _
cbRequired, _
nEntries)
If Not Success Then
Debug.Print "Error enumerating printers."
Exit Sub
End If
End If
Debug.Print "There are " & nEntries & _
" local and connected printers."
For I = 0 To nEntries - 1
PName = Space$(StrLen(Buffer(I * 3)))
Temp = PtrToStr(PName, Buffer(I * 3))
SName = Space$(StrLen(Buffer(I * 3 + 1)))
Temp = PtrToStr(SName, Buffer(I * 3 + 1))
Attrib = Buffer(I * 3 + 2)
Debug.Print "Printer: " & PName, "Server: " & SName, _
"Attributes: " & Hex$(Attrib)
Next I
Else
Debug.Print "Error enumerating printers."
End If
End Sub
- To test this function, type the following line in the Debug window,
and then press ENTER:
EnumeratePrinters1
The output should be similar to the following:
There are 1 local and connected printers.
8388608 \\NCPRINT\HP5SI@1155,HP LaserJet 5Si MX,HP5SI@1155
\\NCPRINT\HP5SI@1155 \\NCPRINT\HP5SI@1155
If you are using Microsoft Windows NT, type:
EnumeratePrinters4
The output should be similar to the following:
There are 1 local and connected printers.
Printer: \\NCPRINT\HP5SI@1155 Server: \\NCPRINT
Attributes: 10
REFERENCES
For more information about the EnumPrinters function, please refer to the
Win32 SDK.
Additional query words:
Keywords : kbcode kbnetwork kbprg kbprint
Version : WINDOWS:7.0,97
Platform : WINDOWS
Issue type : kbhowto
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