[winapi] Retrieving icons of current user printers

Question

I'm trying to emulate MS Office print dialog's printer selection combobox. The drop-down list contains printer names with large printer icons to the left. On Vista fax printer has a nice fax icon, shared printers are marked, default printer too. Best would be to be able to view some more printer info too, like explorer does viewing Control Panel->Printers.

Any ideas where to start with that?

Had moderate success with SHGetFileInfo but your opinion is most welcome.

[os: windows, code language: any]

Answer 1

It\'s easy and classic in C/Win32 (see Win32 grp, Explorer source code from MS internal)

Answer 2

You don't say how you are calling SHGetFileInfo, but I would guess you need to set the SHGFI_PIDL flag and use a fully qualified PIDL (And maybe SHGFI_USEFILEATTRIBUTES)

To get shared/default overlay icons, set the SHGFI_ADDOVERLAYS flag

Answer 3

Here is what I finally came up with. You'll need IShellFolder Extended Type Library v1.2 for the various OLE interfaces. I'm positive this typelib can be ported in a better way to VB6 but anyway here is the result:

Option Explicit

Private Const CSIDL_PRINTERS    As Long = &H4
Private Const SHGFI_PIDL        As Long = &H8
Private Const SHGFI_ICON        As Long = &H100
Private Const SHGFI_DISPLAYNAME As Long = &H200
Private Const MAX_PATH          As Long = 260

Private Declare Function SHGetDesktopFolder Lib "shell32" (ppshf As IShellFolder) As Long
Private Declare Function SHGetSpecialFolderLocation Lib "shell32.dll" (ByVal hwndOwner As Long, ByVal nFolder As Long, pidl As Long) As Long
Private Declare Sub CoTaskMemFree Lib "ole32.dll" (ByVal pv As Long)
Private Declare Function SHGetFileInfo Lib "shell32" Alias "SHGetFileInfoA" (pszPath As Any, ByVal dwFileAttributes As Long, psfi As SHFILEINFO, ByVal cbFileInfo As Long, ByVal uFlags As Long) As Long
Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (pDest As Any, pSource As Any, ByVal dwLength As Long)
Private Declare Function OleCreatePictureIndirect Lib "olepro32.dll" (lpPictDesc As PICTDESC, riid As Any, ByVal fPictureOwnsHandle As Long, ppRet As IPicture) As Long

Private Type SHFILEINFO
    hIcon               As Long
    iIcon               As Long
    dwAttributes        As Long
    szDisplayName       As String * MAX_PATH
    szTypeName          As String * 80
End Type

Private Type PICTDESC
    Size                As Long
    Type                As Long
    hBmpOrIcon          As Long
    hPal                As Long
End Type

Private Sub Command1_Click()
    Dim IID_IShellFolder As IShellFolderEx_TLB.GUID
    Dim IID_IPicture(0 To 3) As Long
    Dim pidlPrinters()  As Byte
    Dim pidlCurrent()   As Byte
    Dim pidlAbsolute()  As Byte
    Dim pDesktopFolder  As IShellFolder
    Dim pPrintersFolder As IShellFolder
    Dim pEnumIds        As IEnumIDList
    Dim lPtr            As Long
    Dim uInfo           As SHFILEINFO
    Dim uPict           As PICTDESC
    Dim sPrinterName    As String
    Dim oPrinterIcon    As StdPicture

    '--- init consts
    IID_IShellFolder.Data1 = &H214E6 '--- {000214E6-0000-0000-C000-000000000046}
    IID_IShellFolder.Data4(0) = &HC0
    IID_IShellFolder.Data4(7) = &H46
    IID_IPicture(0) = &H7BF80980 '--- {7BF80980-BF32-101A-8BBB-00AA00300CAB}
    IID_IPicture(1) = &H101ABF32
    IID_IPicture(2) = &HAA00BB8B
    IID_IPicture(3) = &HAB0C3000
    '--- init local vars
    uPict.Size = Len(uPict)
    uPict.Type = vbPicTypeIcon
    Call SHGetDesktopFolder(pDesktopFolder)
    '--- retrieve enumerator of Printers virtual folder
    Call SHGetSpecialFolderLocation(0, CSIDL_PRINTERS, lPtr)
    pidlPrinters = pvToPidl(lPtr)
    Call pDesktopFolder.BindToObject(VarPtr(pidlPrinters(0)), 0, IID_IShellFolder, pPrintersFolder)
    Call pPrintersFolder.EnumObjects(0, SHCONTF_NONFOLDERS, pEnumIds)
    '--- loop printers
    Do While pEnumIds.Next(1, lPtr, 0) = 0 '--- S_OK
        pidlCurrent = pvToPidl(lPtr)
        '--- combine pidls: Printers + Current
        ReDim pidlAbsolute(0 To UBound(pidlPrinters) + UBound(pidlCurrent))
        Call CopyMemory(pidlAbsolute(0), pidlPrinters(0), UBound(pidlPrinters) - 1)
        Call CopyMemory(pidlAbsolute(UBound(pidlPrinters) - 1), pidlCurrent(0), UBound(pidlCurrent) - 1)
        '--- retrieve info
        Call SHGetFileInfo(pidlAbsolute(0), 0, uInfo, Len(uInfo), SHGFI_PIDL Or SHGFI_DISPLAYNAME Or SHGFI_ICON)
        sPrinterName = Left(uInfo.szDisplayName, InStr(uInfo.szDisplayName, Chr$(0)) - 1)
        '--- extract icon
        uPict.hBmpOrIcon = uInfo.hIcon
        Call OleCreatePictureIndirect(uPict, IID_IPicture(0), True, oPrinterIcon)
        '--- show
        Set Picture = oPrinterIcon
        MsgBox sPrinterName
    Loop
End Sub

Private Function pvToPidl(ByVal lPtr As Long) As Byte()
    Dim lTotal      As Long
    Dim nSize       As Integer
    Dim baPidl()    As Byte

    Do
        Call CopyMemory(nSize, ByVal (lPtr + lTotal), 2)
        lTotal = lTotal + nSize
    Loop While nSize <> 0
    ReDim baPidl(0 To lTotal + 1)
    Call CopyMemory(baPidl(0), ByVal lPtr, lTotal + 2)
    Call CoTaskMemFree(lPtr)
    pvToPidl = baPidl
End Function