Change activeprinter to one with unknown/changing name

Question

Visual Basic application edition, version 7.1

I would like to:

• search in the list of all available printers that one whose name contains string "P3005"
• change activeprinter to that with name contanining "P3005"

It was easy to find a list of available printers' names, and to select that I was searching for (I used the Filter() command). But activeprinter also needs to specify the Ne: port number, and I can't find it

Answer 1

The NE: numbers change on every computer. You can read that from registry.

Software\Microsoft\Windows NT\CurrentVersion\Devices

Here is a function that reads all the printer names:

Global Const HKEY_CURRENT_USER = &H80000001
Global Const HKEY_LOCAL_MACHINE = &H80000002
Global Const KEY_READ = &H20019
Global Const REG_OPTION_NON_VOLATILE = &H0
Global Const strPrinterKeyPath = "Software\Microsoft\Windows NT\CurrentVersion\Devices"

Declare PtrSafe Function RegOpenKeyEx Lib "advapi32.dll" Alias "RegOpenKeyExA" ( _
    ByVal hKey As LongPtr, ByVal lpSubKey As String, ByVal ulOptions As Long, _
    ByVal samDesired As Long, phkResult As LongPtr) As Long

Declare PtrSafe Function RegQueryValueEx Lib "advapi32.dll" Alias "RegQueryValueExA" ( _
    ByVal hKey As LongPtr, ByVal lpValueName As String, ByVal lpReserved As LongPtr, _
    lpType As Long, lpData As Any, lpcbData As Long) As Long

Declare PtrSafe Function RegCloseKey Lib "advapi32.dll" (ByVal hKey As LongPtr) As Long

Public Sub DebugPrintAllPrinters()
    Dim oReg As Object, i As Long
    Dim strKeyPath As String, strValue As String, Msg As String
    Dim arrPrinter As Variant
    
    Set oReg = GetObject("winmgmts:{impersonationLevel=impersonate}!\\.\root\default:StdRegProv")
    strKeyPath = "Software\Microsoft\Windows NT\CurrentVersion\Devices"
    oReg.EnumValues HKEY_CURRENT_USER, strKeyPath, arrPrinter
    
    For i = 0 To UBound(arrPrinter)
        oReg.GetStringValue HKEY_CURRENT_USER, strKeyPath, arrPrinter(i), strValue
        Msg = Msg & arrPrinter(i) & Replace(strValue, "winspool,", " auf ") & vbCr
    Next
    
    Set oReg = Nothing
    Debug.Print Msg
End Sub

Answer 2

Here's a simple way to set the printer if you know the printer name but not the port number. We can safely assume that the port number for our printer is between 01 and 99. So, we can just loop through all possible options with the printer name and port. When the port number isn't correct, it will error out and we just resume execution in our loop. For the one case where the port number is correct, it will set the printer as the one we want.

Function set_printer()
    
    Dim printer_string As String
    Dim port As Variant
    
    On Error Resume Next
    
    port = 0
    Do While port < 100
        If port < 10 Then
            ' add leading 0
            printer_string = "P3005 on Ne0" + CStr(port) + ":"
            Application.ActivePrinter = printer_string
        Else
            printer_string = "P3005 on Ne" + CStr(port) + ":"
            Application.ActivePrinter = printer_string
        End If
        port = port + 1
    Loop

End Function