Building a multidimensional array in vb.net

Question

I\'m trying to build up a multidimensional array which will hold two bits of info for each record in a database e.g. id, description.

This is what I am currently doi

Answer 1

Try this

Dim mArray(1,1) As String
Dim i As Integer = 0
While cmdReader.Read()
    mArray(i,0) = cmdReader.Item("id")
    mArray(i,1) = cmdReader.Item("description")
    i = i + 1
    ReDim Preserve mArray(i,1)
End While

Answer 2

Correct it by

Dim mArray(,) As String = ""

Answer 3

This works for me:

Dim values As New List(Of Dictionary(Of String, String))()

values.Add(New Dictionary(Of String, String)() From {{"quarter", q1.ToString}, {"year", y1.ToString}})
values.Add(New Dictionary(Of String, String)() From {{"quarter", q2.ToString}, {"year", y2.ToString}})
values.Add(New Dictionary(Of String, String)() From {{"quarter", q3.ToString}, {"year", y3.ToString}})
values.Add(New Dictionary(Of String, String)() From {{"quarter", q4.ToString}, {"year", y4.ToString}})

For Each value As Dictionary(Of String, String) In values
    Dim quarter As String = value("quarter")
    Dim year As String = value("year")
    Debug.Print(quarter & "/" & year)
Next

Answer 4

Why not rather make use of List Class and Dictionary Class

You can rather then create a List of Dictionaries, with the key and value both strings. The key can then represent your key (id and description in your example, and the value can be what ever was stored).

Something like

Dim values As New List(Of Dictionary(Of String, String))()

and then in the while loop something like

values.Add(New Dictionary(Of String, String)() From { _
    {"id", cmdReader.Item("id")} _
})
values.Add(New Dictionary(Of String, String)() From { _
    {"description", cmdReader.Item("description")} _
})

You could then use foreach

For Each value As Dictionary(Of String, String) In values
    Dim id As String = value("id")
    Dim description As String = value("description")
Next

Or a for

For i As Integer = 0 To values.Count - 1
    Dim value As Dictionary(Of String, String) = values(i)
    Dim id As String = value("id")
    Dim description As String = value("description")
Next

Answer 5

The problem is that you are not initializing the array.

This should work, until i will not reach the limits set in the initialization.

Dim mArray(100,100) As String
Dim i As Integer = 0
While cmdReader.Read()
    mArray(i,0) = cmdReader.Item("id")
    mArray(i,1) = cmdReader.Item("description")
    i = i + 1
End While

But if the array limits are not known I suggest to follow astander's suggestion.