How can I tell that a directory is the Recycling bin in VB6?

I am attempting to port the code in this article to VB6, but I'm experiencing crashing. I'm pretty sure my error is in my call to SHBindToParent (MSDN entry) since SHParseDisplayName is returning 0 (S_OK) and ppidl is being set. I admit my mechanism of setting the riid (I used an equivalent type, a UUID) is pretty ugly, but I think it more likely I'm doing something wrong with 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

Solution

I believe your call to SHBindToParent is crashing because you need to pass longs, then use the returned pointers to copy the memory into your types. I found several posts when I googled the SHBindToParent function that mentioned OS support, mostly 95 and 98. When I tried it on XP SP3 I got an error "No such interface supported."

Here is how I modified your code to get past the 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