Come faccio a sapere che una directory è il cestino in VB6?

Question

Sto tentando di porto il codice questo articolo a VB6, ma sto sperimentando crash. Sono abbastanza sicuro che il mio errore è nella mia chiamata a SHBindToParent ( MSDN ) dal SHParseDisplayName sta tornando 0 (S_OK) e ppidl viene impostata. Ammetto il mio meccanismo di impostare la riid (io ho usato un tipo equivalente, un UUID) è abbastanza brutto, ma penso che sia più probabile che sto facendo qualcosa di sbagliato con psf.

Private Declare Function SHParseDisplayName Lib "shell32" (ByVal pszName As Long, ByVal IBindCtx As Long, ByRef ppidl As ITEMIDLIST, sfgaoIn As Long, sfgaoOut As Long) As Long
Private Declare Function SHBindToParent Lib "shell32" (ByVal ppidl As Long, ByRef shellguid As UUID, ByVal psf As Long, ByVal ppidlLast As Long) As Long

Private Sub Main()
    Dim hr As Long
    Dim ppidl As ITEMIDLIST
    Dim topo As String
    Dim psf As IShellFolder
    Dim pidlChild As ITEMIDLIST
    topo = "c:\tmp\" '"//This VB comment is here to make SO's rendering look nicer.
    Dim iid_shellfolder As UUID
    iid_shellfolder.Data1 = 136422
    iid_shellfolder.Data2 = 0
    iid_shellfolder.Data3 = 0
    iid_shellfolder.Data4(0) = 192
    iid_shellfolder.Data4(7) = 70
    hr = SHParseDisplayName(StrPtr(topo), 0, ppidl, 0, 0)
    Debug.Print hr, Hex(hr)
    hr = SHBindToParent(VarPtr(ppidl), iid_shellfolder, VarPtr(psf), VarPtr(pidlChild)) 'Crashes here
End Sub

Answer 1

Credo che la vostra chiamata a SHBindToParent si blocca perché è necessario passare Longs, quindi utilizzare i puntatori restituiti per copiare la memoria nel tipi. Ho trovato diversi posti quando ho cercato su google la funzione SHBindToParent che detto supporto del sistema operativo, per lo più 95 e 98. Quando ho provato su XP SP3 ho ottenuto un errore "Interfaccia non supportata".

Ecco come ho modificato il codice per ottenere oltre il GPF:

Option Explicit

Private Declare Function SHParseDisplayName Lib "shell32" (ByVal pszName As Long, ByVal IBindCtx As Long, ByRef ppidl As Long, ByVal sfgaoIn As Long, ByRef sfgaoOut As Long) As Long
Private Declare Function SHBindToParent Lib "shell32" (ByVal ppidl As Any, ByRef shellguid As UUID, ByRef psf As Any, ByRef ppidlLast As Any) As Long

Private Type SHITEMID
   cb As Long
   abID As Byte
End Type

Private Type ITEMIDLIST
   mkid As SHITEMID
End Type

Private Type UUID
   Data1 As Long
   Data2 As Integer
   Data3 As Integer
   Data4(7) As Byte
End Type


Private Sub Command1_Click()
    Dim hr As Long
    Dim ppidl As Long
    Dim topo As String
    Dim psf As IShellFolder
    Dim pidlChild As Long
    Dim iid_shellfolder As UUID
    Dim lpIDList2 As Long

    topo = "C:\Temp"

    ' create a uuid = {B7534046-3ECB-4C18-BE4E-64CD4CB7D6AC}'
    iid_shellfolder.Data1 = &HB7534046
    iid_shellfolder.Data2 = &H3ECB
    iid_shellfolder.Data3 = &H4C18
    iid_shellfolder.Data4(0) = 190
    iid_shellfolder.Data4(1) = 78
    iid_shellfolder.Data4(2) = 100
    iid_shellfolder.Data4(3) = 205
    iid_shellfolder.Data4(4) = 76
    iid_shellfolder.Data4(5) = 183
    iid_shellfolder.Data4(6) = 214
    iid_shellfolder.Data4(7) = 172

    hr = SHParseDisplayName(StrPtr(topo), ByVal 0&, lpIDList2, ByVal 0&, ByVal 0&)
    ' Debug.Print hr, Hex(hr)'
    hr = SHBindToParent(lpIDList2, iid_shellfolder, psf, pidlChild) 'retuns "No such interface supported" error

End Sub

Answer 2

Un prototipo che ho avuto modo di lavorare, per coloro che possono averne bisogno.

Private Declare Function SHParseDisplayName Lib "shell32" (ByVal pszName As Long, ByVal IBindCtx As Long, ByRef ppidl As Long, ByVal sfgaoIn As Long, ByRef sfgaoOut As Long) As Long
Private Declare Function SHBindToParent Lib "shell32" (ByVal ppidl As Any, ByRef shellguid As UUID, ByRef psf As IShellFolder, ByRef ppidlLast As Any) As Long

Private Sub Main()
    Dim iid_shellfolder As UUID
    Dim hr As Long
    Dim ppidl As Long
    Dim topo As String
    Dim psf As IShellFolder
    Dim pidlChild As Long
    Dim lpIDList2 As Long
    Dim pdid As shdescriptionid
    iid_shellfolder.Data1 = 136422
    iid_shellfolder.Data2 = 0
    iid_shellfolder.Data3 = 0
    iid_shellfolder.Data4(0) = 192
    iid_shellfolder.Data4(7) = 70
    Dim bin As UUID
    bin.Data1 = &H645FF040
    bin.Data2 = &H5081
    bin.Data3 = &H101B
    bin.Data4(0) = &H9F
    bin.Data4(1) = &H8
    bin.Data4(2) = &H0
    bin.Data4(3) = &HAA
    bin.Data4(4) = &H0
    bin.Data4(5) = &H2F
    bin.Data4(6) = &H95
    bin.Data4(7) = &H4E

    'topo = "C:\Temp"
    topo = "c:\$Recycle.Bin\S-1-5-21-725345543-1972579041-1417001333-1192\"
    hr = SHParseDisplayName(StrPtr(topo), ByVal 0&, lpIDList2, ByVal 0&, ByVal 0&)
    hr = SHBindToParent(lpIDList2, iid_shellfolder, psf, pidlChild)
    Dim objShell   As shell32.Shell
    Set objShell = CreateObject("Shell.Application.1") 'New Shell32.Shell        win.Shell.SHGetDataFromIDList psf, pidlChild, SHGDFIL_DESCRIPTIONID, pdid, LenB(pdid)
    Ole32.CoTaskMemFree lpIDList2
    Debug.Print equalUUID(pdid.clsid, bin)
end sub