\nToday’s “Little Program”\ndoes two things:\nIt looks for a printer in the Printers folder,\nand then once it finds it, it creates a shortcut to that printer.\n<\/P>\n
\nAs is common with “Little Programs”,\nI don’t bother with error checking.\nI’ll leave you to do that.\n<\/P>\n
\nSecond part first, since it is handy on its own:\nCreating a shortcut to an arbitrary item in the shell namespace,\nprovided either in the form of an ID list or a shell item.\n(The ID list is the thing that identifies an item in the shell namespace.)\n<\/P>\n
\nvoid CreateShortcutToIDList(PCWSTR pszName, PCUIDLIST_ABSOLUTE pidl)\n{\n CComPtr<IShellLink> spsl;\n spsl.CoCreateInstance(CLSID_ShellLink);\n spsl->SetIDList(pidl);\n CComQIPtr<IPersistFile>(spsl)->Save(pszName, TRUE);\n}<\/p>\nvoid CreateShortcutToItem(PCWSTR pszName, IShellItem *pitem)\n{\n CComHeapPtr<ITEMIDLIST_ABSOLUTE> spidl;\n CComQIPtr<IPersistIDList>(pitem)->GetIDList(&spidl);\n CreateShortcutToIDList(pszName, spidl);\n}\n<\/PRE>\n
\nNeither of these is particular complicated.\nTo create a shortcut given an ID list:\n<\/P>\n
ShellLink<\/CODE> object.\n- Tell that shell link object to point to our desired ID list.\n
- Save the shell link.\n<\/UL>\n
\nTo create a shortcut given a shell item:\n<\/P>\n
\n- Ask the
IShellItem<\/CODE> for its ID list.\n- Create a shortcut to that ID list.\n<\/UL>\n
\nOkay, now the first half:\nFinding the printer.\nThat is a matter of binding to the Printers folder\nand enumerating its contents.\nWhen we find the one whose name matches the target printer,\nwe declare victory.\n<\/P>\n
\nint __cdecl wmain(int argc, wchar_t **argv)\n{\n CCoInitialize<\/A> init;\n CComPtr<IShellItem> spPrinters;\n SHGetKnownFolderItem(FOLDERID_PrintersFolder, KF_FLAG_DEFAULT,\n nullptr, IID_PPV_ARGS(&spPrinters));\n CComPtr<IEnumShellItems> spEnum;\n spPrinters->BindToHandler(nullptr, BHID_EnumItems,\n IID_PPV_ARGS(&spEnum));\n for (CComPtr<IShellItem> spPrinter;\n spEnum->Next(1, &spPrinter, nullptr) == S_OK;\n spPrinter.Release()) {\n CComHeapPtr<wchar_t> spszName;\n spPrinter->GetDisplayName(SIGDN_NORMALDISPLAY, &spszName);\n wprintf(L”Found printer \\”%ls\\”\\n”, spszName);\n if (lstrcmpiW(spszName, argv[1]) == 0) {\n wprintf(L”Creating shortcut as \\”%ls\\”\\n”, argv[2]);\n CreateShortcutToItem(argv[2], spPrinter);\n }\n }\n return 0;\n}\n<\/PRE>\n\nThis is a little trickier, but not by much.\n<\/P>\n
\n- Initialize COM.\n
- Get the
IShellItem<\/CODE> for the Printers folder.\n- Get the enumerator for the Printers folder.\n
- For each item in the Printers folder:\n
\n - Get its name and print it just for diagnostic purposes.\n
- If the name matches the one we’re looking for,\n then create the shortcut.\n <\/UL>\n<\/UL>\n
\nHere are the header files I used:\n<\/P>\n
\n#define STRICT_TYPED_ITEMIDS<\/A> \/\/ enable stricter type checking on ITEMIDs\n#include <windows.h>\n#include <atlbase.h> \/\/ for CComPtr, CComQIPtr\n#include <atlalloc.h> \/\/ for CComHeapPtr\n#include <shlobj.h> \/\/ for shell interfaces\n#include <knownfolders.h> \/\/ for FOLDERID_PrintersFolder\n#include <stdio.h> \/\/ for wprintf\n<\/PRE>\n\nFor those of you who prefer to work with CSIDLs,\nthe change is relatively minor.\nReplace the SHGetKnownFolderItem<\/CODE>\ncall with\n<\/P>\n\n BindToCsidlItem<\/A>(CSIDL_PRINTERS, &spPrinters);\n<\/PRE>\n\nYou may have noticed that I used\n\nthe for-if anti-pattern<\/A>.\nI could’ve gone for the item directly by using\nSHCreateItemFromRelativeName<\/CODE>:\n<!–\nIShellFolder::ParseDisplayName<\/CODE>:\n–>\n<\/P>\n\nint __cdecl wmain(int argc, wchar_t **argv)\n{\n CCoInitialize init;\n CComPtr<IShellItem> spPrinters;\n SHGetKnownFolderItem(FOLDERID_PrintersFolder, KF_FLAG_DEFAULT,\n nullptr, IID_PPV_ARGS(&spPrinters));\n CComPtr<IShellItem> spPrinter;\n SHCreateItemFromRelativeName(spPrinters, argv[1], nullptr,\n IID_PPV_ARGS(&spPrinter));\n CreateShortcutToItem(argv[2], spPrinter);\n return 0;\n}\n<\/PRE>\n\nAs before,\nif you’re the sort of person who prefers to do things\nold-school, you can parse the name yourself,\nat which point you may as well give up on shell items,\nhike up your pants,\nand do it\n\nwith an onion on your belt<\/A>:\n<\/P>\n\nHRESULT BindToIDList(PCUIDLIST_ABSOLUTE pidl,\n REFIID riid, void **ppv)\n{\n *ppv = nullptr;\n CComPtr<IShellFolder> spsfDesktop;\n HRESULT hr = SHGetDesktopFolder(&spsfDesktop);\n if (SUCCEEDED(hr)) {\n if (pidl->mkid.cb) {\n hr = spsfDesktop->BindToObject(pidl, nullptr, riid, ppv);\n } else {\n hr = spsfDesktop->QueryInterface(riid, ppv);\n }\n }\n return hr;\n}<\/p>\nint __cdecl wmain(int argc, wchar_t **argv)\n{\n CCoInitialize init;\n CComHeapPtr<ITEMIDLIST_ABSOLUTE> spidlPrinters;\n SHGetSpecialFolderLocation(nullptr,\n CSIDL_PRINTERS, &spidlPrinters);\n CComPtr<IShellFolder> spsfPrinters;\n BindToIDList(spidlPrinters, IID_PPV_ARGS(&spsfPrinters));<\/p>\n
ULONG cchEaten;\n DWORD dwAttributes = 0;\n CComHeapPtr<ITEMIDLIST_RELATIVE> spidl;\n spsfPrinters->ParseDisplayName(nullptr, nullptr, argv[1],\n &cchEaten, &spidl, &dwAttributes);<\/p>\n
CComHeapPtr<ITEMIDLIST_ABSOLUTE> spidlPrinter;\n spidlPrinter.Attach(ILCombine(spidlPrinters, spidl));\n CreateShortcutToIDList(argv[2], spidlPrinter);\n return 0;\n}\n<\/PRE>\n