[RESOLVED] API call not working

This is code from John Walkenbach's book "Excel 2000 Power Programming with VBA":

VB Code:

Option Explicit
 
'32-bit API declarations
Declare Function SHGetPathFromIDList Lib "shell32.dll" _
    Alias "SHGetPathFromIDListA" (ByVal pidl As Long, ByVal _
    pszpath As String) As Long
 
Declare Function SHBrowseForFolder Lib "shell32.dll" _
    Alias "SHBrowseForFolderA" (lpBrowseInfo As BrowseInfo) _
    As Long
 
Public Type BrowseInfo
    hOwner As Long
    pIDLRoot As Long
    pszDisplayName As String
    lpszTitle As String
    ulFlags As Long
    lpfn As Long
    lParam As Long
    iImage As Long
End Type
 
Function GetDirectory(Optional msg) As String
    Dim bInfo As BrowseInfo
    Dim path As String
    Dim r As Long, x As Long, pos As Integer
    
    'Root folder = Desktop
    bInfo.pIDLRoot = 0&
    
    'Title in the dialog
    If IsMissing(msg) Then
        bInfo.lpszTitle = "Please select the folder where 'Old Bio-Analytical MS.xls' exists."
    Else
        bInfo.lpszTitle = msg
    End If
    
    'Type of directory to return
    bInfo.ulFlags = &H1
    
    'Display the dialog
    x = SHBrowseForFolder(bInfo)
    
    'Parse the result
    path = Space$(512)
    r = SHGetPathFromIDList(ByVal x, ByVal path)
    If r Then
        pos = InStr(path, Chr$(10))
        [COLOR=Red]GetDirectory = Left(path, pos - 1)[/COLOR]
    Else
        GetDirectory = ""
    End If
End Function
 
Sub GetAFolder()
    Dim msg As String
    msg = "Please select a location for the backup."
    MsgBox GetDirectory(msg)
End Sub

The Sub at the bottom is just a test for the call...which isn't working :(

I get the error where the red text is. Apparently variable pos = 0 :confused:

Any ideas????

I added some comments here:

Code:

---

    'Parse the result
'This establishes a buffer for the returned string
    path = Space$(512)
'Fetch the string
    r = SHGetPathFromIDList(ByVal x, ByVal path)
    If r Then
'Find an ASCII Line Feed in the string ???
        pos = InStr(path, Chr$(10))
'The Directory is the string up to, but not including the Line Feed
        GetDirectory = Left(path, pos - 1)
    Else
        GetDirectory = ""
    End If

---

If there is no Line Feed in the returned string, the result of the "pos" line is zero (0), and the next line will try to find the left part of the string starting at position -1, which is invalid and will give you the error message. You'll just have to find out the actual contents of the string so that you can parse it. Since there are obviously non-printing characters embedded in the string, you might insert a test loop to walk through the string character by characters showing you the codes for each character. Then you can figure out how to parse it. Maybe the line separator is not actually "10" (Line Feed), but perhaps "13" Carriage Return? (Just a guess).

Thanks for the info Webtest. I actually looped from character 1 to 255 to find the right one and I couldn't :confused:

I had this post on another website and it was solved there.

And apparently Windows stores strings with a null to flag the end of the string. Char(0) is that null.

So Char(0) it is! :)