Multidimensional dynamic Arrays in vb.net

[carlblanchard]

Hi Everyone,

Ive come across the need for a Multidimensional dynamic Array however its causing a headache so can anyone shed any light on the matter...

Dim CusArray(,)
                Dim i, j As Integer
                i = 0
                j = 0
 
                While MyReader.Read
                    CusArray(i, 0) = "1" 'MyReader("CustomerId")
                    CusArray(i, 1) = "Carl Blanchard" 'MyReader("FullName")
                End While
                ReDim Preserve CusArray(LBound(CusArray), UBound(CusArray))
 
                MsgBox(CusArray(0, 0))

I get this error saying "Object reference not set to the instance of the object" which is caused my CusArray(i, 0) = "1" 'MyReader("CustomerId") However if i try and Dim CusArray(,) as New Array it dosnt allow me just says Arrays cant not be declared with New- ive read loads of posts on here but none help, most of them are vb6 and not .net,


I will know the size of the size of the subscript which will be max of 11 however this array is made up from records out of my db so i will not know the size of the Index......


Can any one help, code examples would be good

thanks Carl

[persianboy]

try setting initial values for each dimension when declaring the array

dim CusArray(1,1)

[carlblanchard]

OK Cool that worked however i get an error now on line

CusArray(i, 1) = "Carl Blanchard" 'MyReader("FullName")

Saying

Index was outside the bounds of the array ???????

[persianboy]

anyway you cant redim a multidimensional array ( you can redim only the last dimenstio ), take a look at system.collections namespace, maybe those classes will make your life easier
( hashtable might work fine in your case )

[persianboy]

what i could think of is using a hashtable, the keys are your first dimenstion and add an arraylist object as the value for each key which will act like your second dimension,

there might be better ways, it depends on how you want to retrieve the data and other factors

[carlblanchard]

NOT WORKING READ THIS POST

[carlblanchard]

ok heres current code

Dim CusArray(0, 9)
                Dim i As Integer
                i = -1
 
                While MyReader.Read
                    i = i + 1
                    'ReDim CusArray(i, 9)
                    CusArray(i, 0) = MyReader("CustomerId")
                    CusArray(i, 1) = MyReader("FullName")
                    CusArray(i, 2) = MyReader("Company")
                    CusArray(i, 3) = MyReader("BillingBuilding")
                    CusArray(i, 4) = MyReader("BillingStreet")
                    CusArray(i, 5) = MyReader("BillingStreet2")
                    CusArray(i, 6) = MyReader("BillingTown")
                    CusArray(i, 7) = MyReader("BillingCounty")
                    CusArray(i, 8) = MyReader("BillingPostCode")
                    CusArray(i, 9) = MyReader("BillingCountry")
                    'msgbox(cusArray(i,1))
                End While

here the problem,
My DB is returning 3 records fine.

However i get index out of range because - Dim CusArray(0, 9) is fixing the size to 1 index and 9 subscripts
so incomes Redim CusArray(i,9) now i get with the message box.
3 results 1 = blank 2 = blank 3 = Name
This is because theres no preserve on the redim, however i cant redim the array with preserve because that only does the rightmost index - therefore im rowing up a stream without a paddle.........

How can i make this array Dynamic ?????

[carlblanchard]

i remember a friend of my when we were doing something liek this in ASP he managed to reverse it so instead of it being the last index that was preserved it would preserve the first one.

he added something like reverse or rev when redimming the array. Any ideas ?

[<ABX]

'not tested but it should :D work (too lazy to make a mockup of ur MyReader)
 
        Dim colCustomers As Collection
        Dim strArray(9) As String
        'Dim CusArray(0, 9)
 
        While MyReader.Read
 
            strArray(0) = MyReader("CustomerId")
            strArray(1) = MyReader("FullName")
            strArray(2) = MyReader("Company")
            strArray(3) = MyReader("BillingBuilding")
            strArray(4) = MyReader("BillingStreet")
            strArray(5) = MyReader("BillingStreet2")
            strArray(6) = MyReader("BillingTown")
            strArray(7) = MyReader("BillingCounty")
            strArray(8) = MyReader("BillingPostCode")
            strArray(9) = MyReader("BillingCountry")
 
            'Add To Collection
            colCustomers.Add(strArray)
        End While
 
        'Now Im guessing that you really need the data in a 
        'multi-dimetimetion array
 
        Dim cusArray(colCustomers.Count - 1, 9)
 
        Dim I As Integer
        Dim X As Integer
 
        For I = 0 To colCustomers.Count - 1
            For X = 0 To 9
                strArray = colCustomers.Item(I + 1)
                cusArray(I, X) = strArray(X)
            Next
        Next