windows - Incorrect folder locations returned from SHGetPathFromIDList -

i trying restrict users access location (windows, program files, etc.) , doing implementing ifolderfilter interface.

everything seems going fine until shouldshow function gets called , seems fall apart. initial folder pass in of c:\programdata\company\app\year , see that, file dialog shows hanging off desktop why when inspect folders contained in pidl c:\users\graham.reeds\desktop\windows, c:\users\graham.reeds\desktop\program files, etc. seemingly preventing them being matched csidl_ variables want prevent user selecting.

i tried using shgetpathfromidlistex , shgetknownfolderidlist vs2010 gives me 'identifier x undefined' including shlobj , link shell32.lib.

hresult stdmethodcalltype shouldshow(ishellfolder* sf, lpcitemidlist pidlfolder, lpcitemidlist pidlitem)   {       hresult resultcode = s_ok;       ulong attributes = 0ul;        if (succeeded(sf->getattributesof(1, &pidlitem, &attributes)))       {         char szpath[_max_path];         bool f = shgetpathfromidlist(pidlitem, szpath); //      bool f = shgetpathfromidlistex(pidlitem, szpath, _max_path, 0);          // folderid_windows / csidl_windows         pidlist_absolute pidl; //      if (succeeded(shgetknownfolderidlist(folderid_windows, 0, 0, &pidl)))         if (succeeded(shgetfolderlocation(0, csidl_windows, 0, 0, &pidl)))         {             hresult hres = sf->compareids(0, pidlitem, pidl);             if ((short)hresult_code(hres) == 0)             {                 resultcode = s_false;             }             ilfree(pidl);         }     }     return resultcode;   } 

what need able prevent folders appearing in browse folder. how can that?

shgetpathfromidlist requires absolute pidl (one starting desktop @ top of namespace heirarchy , working down), passing pidlitem single child pidl (pidlitem relative pidlfolder, not desktop).

instead of using shgetpathfromidlist can use ishellfolder::getdisplaynameof shgdn_forparsing flag full path of item (e.g. sf->getdisplaynameof(pidlitem, ...)).

the same problem happening compareids call. ishellfolder::compareids requires 2 pidls both relative specified folder, trying call 1 relative pidl , 1 absolute one.

one solution create absolute pidl out of pidlfolder , pidlitem using ilcombine , pass compareids, need use desktop folder comparison (you obtain shgetdesktopfolder) rather using sf.