Using “pure” VB, the only way to build a generic routine that returns the number of dimensions of an array passed as an argument is using a loop that repeatedly tests the LBound (o UBound) function until it fails:
Function ArrayDims(arr As Variant) As Integer Dim i As Integer, bound As Long On Error Resume Next For i = 1 To 60 bound = LBound(arr, i) If Err Then ArrayDims = i - 1 Exit Function End If NextEnd FunctionYou can write a faster routine by peeking at the memory location where Visual Basic holds the number of dimensions of any array:
Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (dest As _ Any, source As Any, ByVal bytes As Long)Function ArrayDims(arr As Variant) As Integer Dim ptr As Long Dim VType As Integer Const VT_BYREF = &H4000& ' get the real VarType of the argument ' this is similar to VarType(), but returns also the VT_BYREF bit CopyMemory VType, arr, 2 ' exit if not an array If (VType And vbArray) = 0 Then Exit Function ' get the address of the SAFEARRAY descriptor ' this is stored in the second half of the ' Variant parameter that has received the array CopyMemory ptr, ByVal VarPtr(arr) + 8, 4 ' see whether the routine was passed a Variant ' that contains an array, rather than directly an array ' in the former case ptr already points to the SA structure. ' Thanks to Monte Hansen for this fix If (VType And VT_BYREF) Then ' ptr is a pointer to a pointer CopyMemory ptr, ByVal ptr, 4 End If ' get the address of the SAFEARRAY structure ' this is stored in the descriptor ' get the first word of the SAFEARRAY structure ' which holds the number of dimensions ' ...but first check that saAddr is non-zero, otherwise ' this routine bombs when the array is uninitialized ' (Thanks to VB2TheMax aficionado Thomas Eyde for ' suggesting this edit to the original routine.) If ptr Then CopyMemory ArrayDims, ByVal ptr, 2 End IfEnd Function
