How to configure an array in VB.NET

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I have been trying to configure an array with a couple of levels in it so I can select "House" "Room" and "Items" where there is a house with 2 rooms and 3 items in each room, so I want to be able to use "House.Room(1).Item(2).Name".
I can setup the array as - House.Room(1).Item(2).Name = "Bedroom"
but then I get the error - 'Object reference not set to an instance of an object.'
If I setup each variable separately it is fine but when I add the array for the rooms and items I cannot access it and I get the above error.
I have tried several options and looked up multiple samples that do not seam to work, I am hoping someone can suggest some changes.

What I have tried:

Structure Pieces
    Public Name1 As String
    Public Name2 As String
    Public Name3 As String
End Structure

Structure EachRoom
    Public Name As String        'holds the room name
    Public Items() As Pieces
    Private Sub Initialize()
        ReDim Items(0 To 3)
    End Sub
End Structure

Structure MyHouse
    Public Name As String
    Public Room() As EachRoom
    Private Sub Initialize()
        ReDim Room(0 To 2)
    End Sub
End Structure
Public House As MyHouse

Posted 11-May-17 13:58pm

Gyzmo

Updated 11-May-17 20:07pm

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[no name] 11-May-17 20:11pm

Learn how to use the debugger.

Richard Deeming 12-May-17 9:33am

None of the code you've posted ever calls the private Initialize methods, so your arrays are never initialized, and will always be Nothing.

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Ralf Meier · Accepted Answer · 2017-05-11T20:07:00

use classes instead of structures ... but notice : classes want to be instantiated ...

VB

Class Pieces
      Public Name1 As String
      Public Name2 As String
      Public Name3 As String

      Public Sub New()
      End Sub
  End Class

  Class EachRoom
      Public Name As String        'holds the room name
      Public Items As New List(Of Pieces)

      Public Sub New()
          For i As Integer = 0 To 3
              Items.Add(New Pieces)
          Next
      End Sub
  End Class

  Class MyHouse
      Public Name As String
      Public Room As New List(Of EachRoom)

      Public Sub New()
          For i As Integer = 0 To 2
              Room.Add(New EachRoom)
          Next
      End Sub
  End Class

  Public House As New MyHouse

Additional like written in the Reply :

VB

Class MyHouse
    Public Name As String
    Public Room As New List(Of EachRoom)

    Public Sub New()
        For i As Integer = 0 To 2
            Room.Add(New EachRoom)
        Next
    End Sub

    Public Sub New(RoomCount as integer) ' with this constructor you can tell the class how much EachRoom you want to have inside it. You are now flexible and not more fixed to 3 EachRoom ...
        For i As Integer = 1 To RoomCount
            Room.Add(New EachRoom)
        Next
    End Sub
End Class