Initialize the dimensions of a multidimensional array according to parameters in VB.net

Question

Hello,

In a VB.Net application I have the following:

• A one-dimensional array containing values.
• A variable containing the number of rows.
• A variable containing the index of each row.
• A variable representing the type of values (uint, string ...).

From these elements, I need to build a multidimensional array corresponding to the number of rows with their index and distribute the values of the one-dimensional array into my new multidimensional array.

My problem is to define my multidimensional array variable from the number of rows, indexes and type of values contained in the variables.

Dim MyArray (index1, Index2,…,….) As Type (uint, string ...)

How can we achieve this functionality?
I need to create an array, not a list.

Thank you.

Answer 1

Hi @jacky Perpète ,
For value types, you can use Buffer.BlockCopy() method to copy arrays, but for reference types, you need to assign multidimensional array manually.
An example of two-dimensional array.

        Dim oneDimensionalArray() As ...  
        Dim index() As Integer = {2, 3}  
  
        Dim multiDimensionalArray As Array  
        Dim arrType As Type = oneDimensionalArray.GetType().GetElementType()  
        multiDimensionalArray = Array.CreateInstance(arrType, index)  
  
        Dim rowIndex, colIndex As Integer  
  
        For i As Integer = 0 To oneDimensionalArray.Length - 1  
            rowIndex = Math.Floor(i / index(1))  
            colIndex = i Mod index(1)  
            multiDimensionalArray(rowIndex, colIndex) = oneDimensionalArray(i)  
        Next  

Hope it could be helpful.

Best Regards,
Xingyu Zhao
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Answer 2

Hello,

Thank you for your reply.
It works very well for numbers of type integer, byte, long etc ...
There is just one problem with the Boolean, String, and DateTime type.

Answer 3

Hello,
Thank you for your reply.

multiDimensionalArray (rowIndex, colIndex) = oneDimensionalArray (i) is not accepted with Option Strict On.
Error BC30574: on disallows late binding.

Here is my tested code that avoids this problem.

Private Function CopyValuetableau2D(Of T)(oneDimensionalArray() As T, TypeTableau As Type, Index() As Integer) As Array

        'Copie les valeurs des éléments du tableau simple dimension vers un tableau 2 dimensions

        Dim index1D As Integer
        Dim myIndicesArray() As Integer

        'Crée le tableau multidimensionnel
        Dim multiDimensionalArray As Array = Array.CreateInstance(TypeTableau, Index)

        'Copie les données du tableau simple dimension vers le tableau multidimensionnel
        For nbIndex0 As Integer = 0 To multiDimensionalArray.GetUpperBound(0)
            For nbIndex1 As Integer = 0 To multiDimensionalArray.GetUpperBound(1)
                myIndicesArray = New Integer() {nbIndex0, nbIndex1}
                multiDimensionalArray.SetValue(oneDimensionalArray(index1D), myIndicesArray)
                index1D = index1D + 1
            Next
        Next

        Return multiDimensionalArray

    End Function

Best regards