ReDim Preserve to a Multi-Dimensional Array in Visual Basic 6 -

i'm using vb6 , need redim preserve multi-dimensional array:

 dim n, m integer     n = 1     m = 0     dim arrcity() string     redim arrcity(n, m)      n = n + 1     m = m + 1     redim preserve arrcity(n, m) 

whenever have written it, following error:

runtime error 9: subscript out of range

because can change last array dimension, in task have change whole array (2 dimensions in example) !

is there workaround or solution this?

as correctly point out, 1 can redim preserve last dimension of array (redim statement on msdn):

if use preserve keyword, can resize last array dimension , can't change number of dimensions @ all. example, if array has 1 dimension, can resize dimension because last , dimension. however, if array has 2 or more dimensions, can change size of last dimension , still preserve contents of array

hence, first issue decide whether 2-dimensional array best data structure job. maybe, 1-dimensional array better fit need redim preserve?

another way use jagged array per pieter geerkens's suggestion. there no direct support jagged arrays in vb6. 1 way code "array of arrays" in vb6 declare array of variant , make each element array of desired type (string in case). demo code below.

yet option implement preserve part on own. you'll need create copy of data preserved , fill redimensioned array it.

option explicit  public sub testmatrixresize()     const max_d1 long = 2     const max_d2 long = 3      dim arr() variant     initmatrix arr, max_d1, max_d2     printmatrix "original array:", arr      resizematrix arr, max_d1 + 1, max_d2 + 1     printmatrix "resized array:", arr end sub  private sub initmatrix(a() variant, n long, m long)     dim long, j long     dim stringarray() string      redim a(n)     = 0 n         redim stringarray(m)         j = 0 m             stringarray(j) = * (m + 1) + j         next j         a(i) = stringarray     next end sub  private sub printmatrix(heading string, a() variant)     dim long, j long     dim s string      debug.print heading     = 0 ubound(a)         s = ""         j = 0 ubound(a(i))             s = s & a(i)(j) & "; "         next j         debug.print s     next end sub  private sub resizematrix(a() variant, n long, m long)     dim long     dim stringarray() string      redim preserve a(n)     = 0 n - 1         stringarray = a(i)         redim preserve stringarray(m)         a(i) = stringarray     next     redim stringarray(m)     a(n) = stringarray end sub