[RESOLVED] VB Crashes when Open Dialog (GetOpenFileNameW) is initialised...

Hello,

Rather than using the Common Dialog, I created it to a Function through API's.

The dialog works fine, without a prob, but it seems like once it is initialised (opened), then when the form unloads VB always crashes.

Is this something to do with it not releasing some handle properly ?
Heres the code. Note: This is the UniCode aware version GetOpenFileNameW

Code:

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Private Declare Function GetOpenFileName Lib "comdlg32.dll" Alias "GetOpenFileNameW" (pOpenfilename As OPENFILENAME) As Long

Private Const OFN_FILEMUSTEXIST = &H1000
Private Const OFN_HIDEREADONLY As Long = &H4

Private Type OPENFILENAME
  lStructSize      As Long
  hWndOwner        As Long
  hInstance        As Long
  lpstrFilter      As Long
  lpstrCustomFilter As Long
  nMaxCustFilter    As Long
  nFilterIndex      As Long
  lpstrFile        As Long
  nMaxFile          As Long
  lpstrFileTitle    As Long
  nMaxFileTitle    As Long
  lpstrInitialDir  As Long
  lpstrTitle        As Long
  flags            As Long
  nFileOffset      As Integer
  nFileExtension    As Integer
  lpstrDefExt      As Long
  lCustData        As Long
  lpfnHook          As Long
  lpTemplateName    As Long
End Type

Public Function cDlgShowOpen(ByVal InitialDir As String, ByVal DialogTitle As String, ByVal Filter As String, ByVal FrmhWnd As Long) As String
On Error GoTo ErrFound

Dim OpenFile As OPENFILENAME
Dim lReturn As Long
Dim strFile As String
Dim FileFilter As String

        strFile = String(512, 0)
        OpenFile.lStructSize = Len(OpenFile)
        OpenFile.hWndOwner = FrmhWnd
        OpenFile.hInstance = App.hInstance
       
          FileFilter = Replace(Filter, "|", vbNullChar)
          If AscW(Right$(FileFilter, 1)) <> 0& Then FileFilter = FileFilter & vbNullChar
        OpenFile.lpstrFilter = StrPtr(FileFilter)
        OpenFile.nFilterIndex = 1
       
        OpenFile.lpstrFile = StrPtr(strFile) 'String(257, 0)
        OpenFile.nMaxFile = Len(strFile)
       
        OpenFile.lpstrFileTitle = StrPtr(OpenFile.lpstrFile)
        OpenFile.nMaxFileTitle = StrPtr(OpenFile.nMaxFile)
        OpenFile.lpstrInitialDir = StrPtr(InitialDir)
        OpenFile.lpstrTitle = StrPtr(DialogTitle)
        OpenFile.flags = OFN_FILEMUSTEXIST Or OFN_HIDEREADONLY
        lReturn = GetOpenFileName(OpenFile)
If lReturn = 0 Then
'Cancel Button Pressed
Else
  cDlgShowOpen = Left$(strFile, InStr(strFile, vbNullChar) - 1)
  'cDlgShowOpen = Replace(OpenFile.lpstrFile, vbNullChar, "")
End If

Exit Function
ErrFound:
cDlgShowOpen = ""
End Function

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Missing last 3 elements of Private Type OPENFILENAME.
Try this:

Code:

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Private Type OPENFILENAME
  lStructSize          As Long    'Length of structure, in bytes
  hwndOwner            As Long    'Window that owns the dialog, or NULL
  hInstance            As Long    'Handle of mem object containing template (not used)
  lpstrFilter          As Long    'File types/descriptions, delimited with vbnullchar, ends with 2xvbnullchar
  lpstrCustomFilter    As Long    'Filters typed in by user
  nMaxCustFilter      As Long    'Length of CustomFilter, min 40x chars
  nFilterIndex        As Long    'Filter Index to use (1,2,etc) or 0 for custom
  lpstrFile            As Long    'Initial file/returned file(s), delimited with vbnullchar for multi files
  nMaxFile            As Long    'Size of Initial File long  , min 256
  lpstrFileTitle      As Long    'File.ext excluding path
  nMaxFileTitle        As Long    'Length of FileTitle
  lpstrInitialDir      As Long    'Initial file dir, null for current dir
  lpstrTitle          As Long    'Title bar of dialog
  Flags                As Long    'See OFN_Flags
  nFileOffset          As Integer  'Offset to file name in full path, 0-based
  nFileExtension      As Integer  'Offset to file ext in full path, 0-based (excl '.')
  lpstrDefExt          As Long    'Default ext appended, excl '.', max 3 chars
  lCustData            As Long    'Appl defined data for lpfnHook
  lpfnHook            As Long    'Pointer to hook procedure
  lpTemplateName      As Long    'Template Name (not used)
  pvReserved          As Long    'new Win2000 / WinXP members
  dwReserved          As Long    'new Win2000 / WinXP members
  FlagsEx              As Long    'new Win2000 / WinXP members
End Type

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Is there a particular reason that you are ignoring errors?

What you have got is only marginally better than bad usage of On Error Resume Next, and that is only because you don't run any more code after the error has occurred.

At an absolute minimum you should have debug code in the error handler, eg:

Code:

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...
Exit Function
ErrFound:
  Debug.Print "Error " & Err.Number & ": " & Err.Description
  Debug.Assert False  'error occurred - check the Immediate window!
  cDlgShowOpen = ""
End Function

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However, it would be better to show the error to the user too - as that way they wont just be wondering why nothing has happened, and complaining to you that it doesn't work (without any option of giving you the details that you need to fix it).

DrUnicode: That seems to have fixed the crashing for now... Thanks

Quote:

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si_the_geek: Is there a particular reason that you are ignoring errors?

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I do actually have a global error checking routine, but I just deleted it in the post (to make the code seem shorter..)

+

When the crash occurs, no error messages appear. Its just a total close of VB.