multidimensional array using list class and dictionary

Question

//Declaration

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

I am trying to create a multidimensional array. this is my code:

con.Open()
ccsfreader = ccsfcomm.ExecuteReader
ccsfreader.Read()
If ccsfreader.HasRows Then
    Do
        values.Add(New Dictionary(Of String, String)() From {{"CostCentre", ccsfreader.Item("CostCentre")}})
        values.Add(New Dictionary(Of String, String)() From {{"ProcessDescription", ccsfreader.Item("ProcessDescription")}})
    Loop While ccsfreader.Read()
End If

con.Close()

For Each value As Dictionary(Of String, String) In values
    Dim CostCentre As String = value("CostCentre")
    Dim ProcessDescription As String = value("ProcessDescription")
    cmblaborcost.Items.Add(CostCentre)
Next

My error is: The given key was not present in the dictionary.

i want an output like this:

1 => array(
CostCentre=>10.00
ProcessDescription=>"up"
)
2 => array(
CostCentre=>20.00
ProcessDescription=>"sided"
)
3 => array(
CostCentre=>110.00
ProcessDescription=>"cutted"
)

Can you show us your declaration of values, and cmblabourcost. Thank you — Cyassin
– Cyassin, Commented Apr 21, 2014 at 0:21

har07 · Accepted Answer · 2014-04-21 01:03:12Z

2

You have two dictionaries in the list. One of which contains only "CostCentre" key, and the other contains only "ProcessDescription" key. So when you try to access both keys from a dictionary, one key must be missing.

You may want to use List(Of Tuple(Of String, String)) instead of List(Of Dictionary(Of String, String)). This example works for me :

Dim values As New List(Of Tuple(Of String, String))
values.Add(Tuple.Create("a1", "a2"))
values.Add(Tuple.Create("b1", "b2"))
values.Add(Tuple.Create("c1", "c2"))

'generate array from List of Tuple'
Dim result = values.Select(Function(x) New String() {x.Item1, x.Item2}).ToArray()
For Each s As String() In result
    Console.WriteLine(s(0) & ", " & s(1))
Next

And for your case, it could be something like this :

'example to add item to list'
Dim values As New List(Of Tuple(Of String, String))
......
If ccsfreader.HasRows Then
    Do
        'values.Add(Tuple.Create(ccsfreader.Item("CostCentre"), ccsfreader.Item("ProcessDescription"))'
        values.Add(New Tuple(Of String, String)(ccsfreader.Item("CostCentre"), ccsfreader.Item("ProcessDescription")))
    Loop While ccsfreader.Read()
End If

.......
'example to access item from list'
For Each value As Tuple(Of String, String) In values
    Dim CostCentre As String = value.Item1
    Dim ProcessDescription As String = value.Item2
    cmblaborcost.Items.Add(CostCentre)
Next

edited Apr 21, 2014 at 1:03

answered Apr 21, 2014 at 0:28

har07

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9 Comments

Maychell Alcorin Over a year ago

i just follow this link stackoverflow.com/questions/4255308/…

Maychell Alcorin Over a year ago

im using vb 2010. .NET 4.5.1

har07 Over a year ago

okay, I'm not sure how it was working in the post you linked to. Anyway, since Tuple if already available in .NET version you're using, I post an alternative using list of Tuple, this approach works fine for me here.

Maychell Alcorin Over a year ago

thank you har07 but i have an error of this :Value of type 'System.Tuple(Of Object, Object)' cannot be converted to 'System.Tuple(Of String, String)'

har07 Over a year ago

hmm.. Seems that it is inferred wrongly as Tuple(Of Object, Object). Try to create the tuple using explicit type declaration : New Tuple(Of String, String)(value1, value2)

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