How to handle a large number of multiselected files with the VB6 common dialog?

Posted on 2004-04-07
Medium Priority
Last Modified: 2012-06-22
With multi-select, I use these settings for the VB6 common dialog
CommonDialog3.flags = cdlOFNAllowMultiselect Or cdlOFNFileMustExist Or cdlOFNExplorer
CommonDialog3.MaxFileSize = 10240

Beyond about 50 files selected, the files don't get identified. and therefore processeed. If I increase the MaxFileSize by a large amount, things freeze up.

Is there a workaround, or a way to warn the user not to select so many files, or am I missing something in my code?

From the experts, advice please!
Question by:Gordon_Atherley
LVL 17

Expert Comment

ID: 10776655
I just selected about 600 with no problems using what you did (flags and maxfilesize). Using version 6.0 of the control (SP3)..

Private Sub Form_Load()
    Dim sSplit() As String
    CommonDialog1.Flags = cdlOFNAllowMultiselect Or cdlOFNFileMustExist Or cdlOFNExplorer
    CommonDialog1.MaxFileSize = 10240
    sSplit = Split(CommonDialog1.FileName, Chr(0))
    MsgBox UBound(sSplit)
End Sub
LVL 26

Expert Comment

ID: 10777338
what sp you are using?

the max number for MaxFileSize is 32k

Author Comment

ID: 10779250

SP 5

The 32k limit explains the problem I am running into. Are there any ways to effectively extend this or to warn users to limit their selections to a particular number? Even so, this would be a nuisance because it's not easy for the user to count the number of files selected.
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LVL 17

Accepted Solution

zzzzzooc earned 1000 total points
ID: 10780063
>> it's not easy for the user to count the number of files selected.

More so the length of all of the files selected. Your files must be really deep inside folders for you to go over 32k file length from under 50 selected files. I can select a couple thousand files in the system32 directory ok.

Anyways.. you could error-handle it and warn the users by the dialog title..  just an idea.. :P

Private Sub Command1_Click()
    On Error Resume Next
    Dim sArray() As String
    With CommonDialog1
        .DialogTitle = "Open file..."
        .Flags = cdlOFNAllowMultiselect Or cdlOFNExplorer
        .InitDir = "c:\windows\system32\"
        .MaxFileSize = 3200
        Call .ShowOpen
        'May not be the same Err # for you..
        If Err.Number = 20476 Then
            .DialogTitle = "Too many files selected. Try again."
            .FileName = vbNullString
            GoTo OpenAgain
            If .FileName <> vbNullString Then
                sArray = Split(.FileName, vbNullChar)
                MsgBox UBound(sArray)
                .FileName = vbNullString
            End If
        End If
    End With
End Sub


Expert Comment

ID: 10782422
If the problem persists, create your own dialogue.

Author Comment

ID: 10782431
Thanks, zzzzzzooc, just what I was looking for.

The files are deep inside folders. Even so, I can't see how they create a file 32k in size. I've still to figure out that puzzle. But the two stage error handler solves the immediate problem.

LVL 17

Expert Comment

ID: 10787798
Oh.. it's not a matter of the length of one file. More so the combined length of all selected files being over 32k. It's still hard imagining the files being about 500+ characters long each though. :o

Author Comment

ID: 10787825
I'm going to explore further. If I find anything useful, I'll post it. :G

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