How do I save (and load) a 2 dimensional array

Question

Hi I'm new to VB and struggling with saving and loading to a file. I am using Visual Studio Express 2008.

I have an array as follows:

Dim m(100,100) As node
Public Structure node
    Public i As Integer
    Public s As String
    Public b As Boolean
End Structure


and I'd like to save to a file the m array.

I am not particularly bothered about data security and looked at xml serialization but cannot get this to work to save the m array.

Is this even possible?

Please can someone provide the code for save & load? I'd be grateful as I've spent ages trying to learn and search for the answer.

Answer 1

XML serialization is probabaly the best way to do it, but you may need to create separate lists - that is, process the XML stream as 100 one-dimensional lists.   If you can indicate the structures and coding you were using for XML serialization, someone may be able to assist wth getting it to work.

Answer 2

As someone who hasnt done anything with serialization this is what i would do: 

1) saving

        Dim m(100, 100) As node

        ''-=create data set
        Dim ds As New DataSet
        ds.Tables.Add("Dim1")
        ds.Tables("Dim1").Columns.Add("i")
        ds.Tables("Dim1").Columns.Add("s")
        ds.Tables("Dim1").Columns.Add("b")
        ds.Tables("Dim1").Columns.Add("dim1")
        ds.Tables("Dim1").Columns.Add("dim2")

        ''-=put data into data set
        For dim1 As Integer = 0 To 100
            For dim2 As Integer = 0 To 100
                Dim row As DataRow = ds.Tables("Dim1").NewRow
                row.Item("i") = m(dim1, dim2).i.ToString
                If m(dim1, dim2).s Is Nothing Then
                    row.Item("s") = ""
                Else
                    row.Item("s") = m(dim1, dim2).s.ToString
                End If

                row.Item("b") = m(dim1, dim2).b.ToString

                row.Item("dim1") = dim1
                row.Item("dim2") = dim2

                ds.Tables("Dim1").Rows.Add(row)
            Next
        Next

        ''-=save dataset
        ds.WriteXml("data.xml")

2) loading

        ''-=load data into data set
        ds = New DataSet
        ds.ReadXml("data.xml")

        ''-=put data into array
        Dim m2(100, 100) As node
        For Each row As DataRow In ds.Tables(0).Rows
            m2(row.Item("dim1"), row.Item("dim2")).i = row.Item("i")
            m2(row.Item("dim1"), row.Item("dim2")).s = row.Item("s")
            m2(row.Item("dim1"), row.Item("dim2")).b = row.Item("b")
 
        Next

It's a lame way to do it but a way nonetheless :)

---

Cheers!

Answer 3

Many thanks to you naurispunk. Nice one.

If the VB lanugage creators can't implement something like support for saving multidimensional ararys e.g m.Writexml("data.xml") which would be elegant, you have to create something else. Lame or not, just tried your code and it work immediately.

Thank you.

Answer 4

A lower tech solution might be to join the values in a delimited string (commas between entries, semi-colons between rows, or something). Then you can use Split to read the values and break them apart.

But naurispunk's solution is quite elegant.

Rod

Rod Stephens
www.vb-helper.com