VBA check if array is one dimensional

Question

I have an array (that comes from SQL) and can potentially have one or more rows.

I want to be able to figure out if the array has just one row.

UBound doesn\

Answer 1

I found Blackhawks's accepted and revised answer very instructive, so I played around with it and learned some useful things from it. Here's a slightly modified version of that code that includes a test sub at the bottom.

Option Explicit

Private Declare Sub CopyMemory Lib "kernel32.dll" Alias "RtlMoveMemory" ( _
    ByVal Destination As Long, ByVal Source As Long, ByVal Length As Integer)

Public Function GetDims(VarSafeArray As Variant) As Integer
    Dim variantType As Integer
    Dim pointer As Long
    Dim arrayDims As Integer

    'The first 2 bytes of the VARIANT structure contain the type:
    CopyMemory VarPtr(variantType), VarPtr(VarSafeArray), 2&

    If Not (variantType And &H2000) > 0 Then
    'It's not an array. Raise type mismatch.
        Err.Raise (13)
    End If

    'If the Variant contains an array or ByRef array, a pointer for the _
        SAFEARRAY or array ByRef variant is located at VarPtr(VarSafeArray) + 8:
    CopyMemory VarPtr(pointer), VarPtr(VarSafeArray) + 8, 4&

    'If the array is ByRef, there is an additional layer of indirection through_
    'another Variant (this is what allows ByRef calls to modify the calling scope).
    'Thus it must be dereferenced to get the SAFEARRAY structure:
    If (variantType And &H4000) > 0 Then 'ByRef (&H4000)
        'dereference the pointer to pointer to get actual pointer to the SAFEARRAY
        CopyMemory VarPtr(pointer), pointer, 4&
    End If
    'The pointer will be 0 if the array hasn't been initialized
    If Not pointer = 0 Then
        'If it HAS been initialized, we can pull the number of dimensions directly _
            from the pointer, since it's the first member in the SAFEARRAY struct:
        CopyMemory VarPtr(arrayDims), pointer, 2&
        GetDims = arrayDims
    Else
        GetDims = 0 'Array not initialized
    End If
End Function

Sub TestGetDims()
' Tests GetDims(). Should produce the following output to Immediate Window:
'
' 1             One
' 2             Two
' Number of array dimensions: 2

    Dim myArray(2, 2) As Variant
    Dim iResult As Integer
    myArray(0, 0) = 1
    myArray(1, 0) = "One"
    myArray(0, 1) = 2
    myArray(1, 1) = "Two"

    Debug.Print myArray(0, 0), myArray(1, 0)
    Debug.Print myArray(0, 1), myArray(1, 1)

    iResult = GetDims(myArray)

    Debug.Print "Number of array dimensions: " & iResult
End Sub