SHBrowseForFolder

Hi, i would like to use the SHBrowseForFolder API in vb.net
this site

i copied it to my vb.net program, i changed all the long's to integers because intergs now are 32bit, Replaced Type with Structure

and used this code to run it...

VB Code:

Dim bi As New BROWSEINFO()
 
        Dim pidl As Integer
 
        bi.hOwner = Me.Handle.ToInt32
        bi.pidlRoot = 0&
        bi.lpszTitle = "Select Directory"
        bi.ulFlags = BIF_RETURNONLYFSDIRS
 
        pidl = SHBrowseForFolder(bi)
 
        Call CoTaskMemFree(pidl)

now if i run that, i get a error on line
pidl = SHBrowseForFolder(bi) with this error..

Additional information: Object reference not set to an instance of an object.

can someone please explain what is wrong?

thanks

P.S nearly 100 Posts :)

Show us the Structure please,
anyway, the problem should be solved by changing

VB Code:

pidl = SHBrowseForFolder(bi)

to

VB Code:

pidl = new SHBrowseForFolder(bi)

I got it without the 'NEW' addition. This is what I use in VB.NET.

Private Structure BROWSEINFO
Dim hOwner As Integer
Dim pidlRoot As Integer
Dim pszDisplayName As String
Dim lpszTitle As String
Dim ulFlags As Integer
Dim lpfn As Integer
Dim lParam As Integer
Dim iImage As Integer
End Structure

Private Const BIF_RETURNONLYFSDIRS As Short = &H1S
Private Const BIF_DONTGOBELOWDOMAIN As Short = &H2S
Private Const BIF_STATUSTEXT As Short = &H4S
Private Const BIF_RETURNFSANCESTORS As Short = &H8S
Private Const BIF_BROWSEFORCOMPUTER As Short = &H1000S
Private Const BIF_BROWSEFORPRINTER As Short = &H2000S
Private Const MAX_PATH As Short = 256

Private Declare Function SHGetPathFromIDList Lib "shell32.dll" Alias "SHGetPathFromIDListA" (ByVal nPidl As Integer, ByVal pszPath As String) As Integer
Private Declare Function SHBrowseForFolder Lib "shell32.dll" Alias "SHBrowseForFolderA" (ByRef lpBrowseInfo As BROWSEINFO) As Integer
Private Declare Sub CoTaskMemFree Lib "ole32.dll" (ByVal PV_Renamed As Integer)

Public Function BrowseFolder(ByRef sTitle As String, ByRef frm As System.Windows.Forms.Form) As String
On Error Resume Next

Dim browse As BROWSEINFO
Dim nPidl As Integer
Dim sPath As String
Dim nPos As Short
Dim sReturn As String

sReturn = ""
browse.hOwner = frm.Handle.ToInt32
browse.pidlRoot = 0
browse.lpszTitle = sTitle
browse.ulFlags = BIF_RETURNONLYFSDIRS
nPidl = SHBrowseForFolder(browse)
sPath = Space(MAX_PATH)
If SHGetPathFromIDList(nPidl, sPath) Then
nPos = InStr(sPath, Chr(0))
sReturn = Left(sPath, nPos - 1)
End If
Call CoTaskMemFree(nPidl)
BrowseFolder = sReturn
End Function


EXAMPLE:
Dim ChosenFolder As String = BrowseFolder("Where Do You Want To Place Your Files", Me)

Please, Please always put your code between vbcode tags!

VB Code:

Private Structure BROWSEINFO 
Dim hOwner As Integer 
Dim pidlRoot As Integer 
Dim pszDisplayName As String 
Dim lpszTitle As String 
Dim ulFlags As Integer 
Dim lpfn As Integer 
Dim lParam As Integer 
Dim iImage As Integer 
End Structure 
 
Private Const BIF_RETURNONLYFSDIRS As Short = &H1S 
Private Const BIF_DONTGOBELOWDOMAIN As Short = &H2S 
Private Const BIF_STATUSTEXT As Short = &H4S 
Private Const BIF_RETURNFSANCESTORS As Short = &H8S 
Private Const BIF_BROWSEFORCOMPUTER As Short = &H1000S 
Private Const BIF_BROWSEFORPRINTER As Short = &H2000S 
Private Const MAX_PATH As Short = 256 
 
Private Declare Function SHGetPathFromIDList Lib "shell32.dll" Alias "SHGetPathFromIDListA" (ByVal nPidl As Integer, ByVal pszPath As String) As Integer 
Private Declare Function SHBrowseForFolder Lib "shell32.dll" Alias "SHBrowseForFolderA" (ByRef lpBrowseInfo As BROWSEINFO) As Integer 
Private Declare Sub CoTaskMemFree Lib "ole32.dll" (ByVal PV_Renamed As Integer) 
 
Public Function BrowseFolder(ByRef sTitle As String, ByRef frm As System.Windows.Forms.Form) As String 
On Error Resume Next 
 
Dim browse As BROWSEINFO 
Dim nPidl As Integer 
Dim sPath As String 
Dim nPos As Short 
Dim sReturn As String 
 
sReturn = "" 
browse.hOwner = frm.Handle.ToInt32 
browse.pidlRoot = 0 
browse.lpszTitle = sTitle 
browse.ulFlags = BIF_RETURNONLYFSDIRS 
nPidl = SHBrowseForFolder(browse) 
sPath = Space(MAX_PATH) 
If SHGetPathFromIDList(nPidl, sPath) Then 
   nPos = InStr(sPath, Chr(0)) 
   sReturn = Left(sPath, nPos - 1) 
End If 
Call CoTaskMemFree(nPidl) 
BrowseFolder = sReturn 
End Function 
 
 
EXAMPLE: 
Dim ChosenFolder As String = BrowseFolder("Where Do You Want To Place Your Files", Me)

Yep, your right, sorry about that, thanks for fixing :-)

c# assembly for SHBrowseForFolder

You should be able to drop this into your VB program without a problem...