Test if array contains any elements?

[vknierim]

Hi,

does anyone have an idea how I can test if an array contains ANY elements?
What I'm trying to do is to pass an array as the first parameter of a function together with a new value for this array as the second parameter of the function. This function should append the new value to the array and return the array. The function is then called repeatedly to append new elements to the array.

The problem I can't solve is how to determine if the passed array has ANY element in it (this will be the case when the function is called for the first time). I need to determine the correct Ubound of the array to properly expand it.

Any Ideas on how to do that would be greatly appreciated.

Thanks

Volker

 

[Kodo]

if isarray(arrayname) then
'do something
else
'do something else
end if

 

[vknierim]

Hello,

I tried that, but the IsArray() function always returns true. The function looks like this

private function add_to_array(aryArg1() as String, strArg2 as String) as String()
Dim x as Long

If IsArray(aryArg1) then
   x = Ubound(aryArg1) +1
   Redim aryArg1(x)
else
   Redim aryArg1(0)
endif

....

And the function is called like this

Dim aryTest() as String
...
aryTest = add_to_array(aryTest, "Hello")
...

The program always stops with an error when it tries to assign

   x = Ubound(aryArg1) + 1

with an "Array Index out of bounds" error which is reasonable because the passed array hasn't been "dimensioned" yet. But I thought the IsArray() function should check for this and the "Else Part" of the code should be executed. But for some strange reason that doesn't happen.
By the way I'm using Access XP under Win 2k.

Volker

 

[vknierim]

Hi,

I found an solution to the problem myself, wich isn't very elegant I think, but at least it works. The following code does the job: the error still occurs but it is catched by the program and then handled appropriatly.

Private Function add_to_array(aryArg1() As String, strArg2 As String) As String()
Dim x As Long 'new "size" of Array
On Error GoTo Handle_Error

x = UBound(aryArg1) + 1
ReDim Preserve aryArg1(x)
' append the new item
aryArg1(x) = strArg2

'return
add_array = arg_Array
Exit Function

Handle_Error:
Select Case Err.Number

Case 9:
    ' Ubound caused Runtime Error No. 9 ,since the array hasn't been dimensioned yet. Set the number of elements x to zero and resume with the code
    x = 0
    Resume Next
Case Else
    ' any other error is displayed on the screen
    MsgBox "Runtime Error " & Err.Number & ": " & Err.Description, vbCritical
End Select
End Function

 

[Mile-O]

Force the error:

Public Function TestArray(aData() As Variant) As Boolean
    On Error GoTo Err_TestArray
   
    Dim intCatch As Integer
    intCatch = UBound(aData()) - LBound(aData())
    TestArray = True
     
Exit_TestArray:
    Exit Function
    
Err_TestArray:
    TestArray = False
    Resume Exit_TestArray

End Function

Just pass your array to the function...

If TestArray(myArray()) Then
    MsgBox "A legal array"
Else
    MsgBox "Not dimensioned array"
End If

 

[vknierim]

Encapsulating the array-test in a separate function is more elegant than my approach. Thanks for the help.