Test an array for empty?

[Whir]

How do you test an array to see if it's empty? Basically, here's what I got:

VB6! Make sure you look at both functions or it probably won't make all that good a sense. Anyway, I need to check to see if aFiles has any data. It errors in the For Each loop if it doesn't. What? I could use For i = 0 to UBound(aFiles)?? I know, I just want to do it this way. And knowing how to test an unset array would be nice too...

Public Sub DirectoryMain()
    Dim Directory As New DirChooser
    Dim sLocation As String
    Dim fMaster As String
    Dim fCopy As String
    Dim aFiles() As String
    Dim sFile As Variant
    
    On Error GoTo ErrorHandler
    sLocation = Directory.GetFolderName
    
    fMaster = "Q:\cad\acad\validation-tool\qc2k.mdb"
    fCopy = sLocation & "qc2k.mdb"
    FileCopy fMaster, fCopy

    aFiles = MakeDrawingArray(sLocation)
    ' TriQuickSortString is an array sorting function not shown here.
    TriQuickSortString aFiles
    
    ' Now here is where I would like to test aFiles
    ' to see if it's been given any data by assigning
    ' it to the MakeDrawingArray function...
    For Each sFile In aFiles
        If UCase(Right(sTemp2, 8)) <> "TITL.DWG" _
        And UCase(Right(sTemp2, 12)) <> "TBLKINFO.DWG" Then
            ThisDrawing.Application.Documents.Open sLocation & sFile
        End If
    Next
    
    Exit Sub
    
ErrorHandler:
    Resume Next
End Sub

Public Function MakeDrawingArray(ByVal sLocation As String)
    Dim aFiles() As String
    Dim sFile As String
    Dim z As Integer
    
    sFile = Dir(sLocation & "*.dwg")
    ReDim aFiles(0) As String
    aFiles(0) = sFile
    sFile = Dir
    z = 1
    
    While sFile <> ""
        ReDim Preserve aFiles(z) As String
        aFiles(z) = sFile
        sFile = Dir
        z = z + 1
    Wend
    
    MakeDrawingArray = aFiles
        
End Function

I think that should do it... Thanks.

-Whir

[zskillz]

you could check to see if the size of the array is 0...

or, you could check to see if each value in the array is 'null' or something like that with a while loop... if a value != 'null', then break from the loop and return that it's not empty.

-Z

[Whir]

If you dim an array as you have to to do what I'm doing 'Dim aFiles() as String' it doesn't support array methods. Therefor, no aFiles.Count. UBound(aFiles) similarly doesn't work if the there are no values in the array, and a For Each temp in aFiles would error because there are no 'temp's in aFiles when it's empty. aFiles(0) will also error because there's nothing there to check.

I thought there was a way to do something like If aFiles Is Empty or something like that, but that only works for a certain type of array and it's not the one I'm using. :P

-Whir

[vass0922]

jeez everybody is doing things the hard way lol

If Not IsEmpty(aArrayName) Then
Set aArrayName = Nothing
End

lol
arghh I rmember that lol....
sorry misread
Have you tried IsNull(aArray) or if aarray Is nothing ?

[Whir]

Ya, I've tried If Not Is Empty, Is Null, Is Nothing... Silly me, I was using a For To statement to ReDim the array. Hey dummy, is your integer 0? No? Then there are values in the array huh? Sometimes I'd like to shoot my fingers for not thinking of this stuff.

Also, you can make a seperate function that uses an error handler, and check for a value in Array(0). If it doesn't error it returns false, if it errors, it hits the error handler and returns true. Found that on Planet Source Code by a guy name Citizen Suicide. Kind of a hack way to do it, but it does work.

After figuring out (FINALLY) how to declare a control's connection to a database after initialization (thanks to MSDN for once) I finally got the app done. It's only been what, four months?

-Whir

[vass0922]

Quote:

After figuring out (FINALLY) how to declare a control's connection to a database after initialization (thanks to MSDN for once) I finally got the app done.

That's why I just do it all in code, no ado controls.
Just put in the correct references and off you go
Requires more code, but far more dynamic.

LOL check to see if element 0 has a value???
Ok now I've done some half a55 before but that's THIN LOL

Do you assign it a default value just in case it really isn't supposed to have a value?
Like if it doesn't have a value put in 0 so its more reliable to test?

[Whir]

No, see, that was another guy's method I found on PSC. I wouldn't do that because it's really hack and I'm not (ya right).

The problem I have with using code for connections is that I have to bind controls to the connection and I have NO idea how to do it. MSDN doesn't give me anything on it, and the guy that used to teach me stuff here doesn't have time anymore. If you have an ADO, or DAO in this case, control you can just bind text boxes to the control and voila, you're done.

To sovle the array problem, I just made my array builder assign Array(0) as False if it doesn't get redimed at all. Then I just test for that. It doesn't make sense, but if you saw the way I built the modules, you'd understand and probably show me an easier way to do it. :P

-Whir

[vass0922]

ahh binding...
I've never really had the oppurtunity to bind...
I always had variable table names, and many times column names so couldn't bind anything through the controls.

arghhh that really sucked making a stored procedure in T-SQL with variable table names

mostly I updated the controls on an event... whether it be changing rows in the recordset or whatever.


-- edit --
Cool, my 2400th post

[Whir]

Ya, that was the other option, which isn't bad, or hard, just a lot more code. :P Call me a wuss, but I'd rather let the controls take care of it, since that's what they're there for. :P

-Whir