Reading Items in an ArrayList

Collapse
This topic is closed.
X
X
Collapse
 
  • Page of 1
  • Time
  • Show
Clear All
new posts
Previous template Next
  • Stuart
    #1

    Reading Items in an ArrayList

    I am using Visual Basic 2005.

    I have created a two dimensional ArrayList named aSystem that is populated as
    follows:-

    aSystem.Add(New PickList(0, "Undefined" ))
    aSystem.Add(New PickList(-1, "Standard UTM"))
    aSystem.Add(New PickList(-2, "UTM-NAD83"))
    aSystem.Add(New PickList(-3, "UTM-NAD27"))

    and then other items are added to the ArrayList from a sorted recordset as
    follows:-

    Do Until ssTemp.EOF
    aSystem.Add(New PickList(ssTemp .Fields("Primar yKey").Value, _
    ssTemp.Fields(" Name").Value))
    ssTemp.MoveNext ()
    Loop

    The structure of the PickList class is as follows:-

    Public Structure PickList

    Private mnPrimaryKey As Integer
    Private msID As String

    Public Sub New(ByVal PrimaryKey As Integer, ByVal ID As String)
    mnPrimaryKey = PrimaryKey
    msID = ID
    End Sub

    Public ReadOnly Property PrimaryKey() As Integer
    Get
    Return mnPrimaryKey
    End Get
    End Property

    Public ReadOnly Property ID() As String
    Get
    Return msID
    End Get
    End Property

    End Structure

    I use the ArrayList to populate a ComboBox

    With cboSystem
    .DataSource = aSystem
    .ValueMember = "PrimaryKey "
    .DisplayMember = "ID"
    End With

    For the most part everything works fine; the ComboBox is populated with all
    the data.

    I have two problems...

    1. I can't seem to read the items from the ArrayList directly. I would
    expect to be
    able to read the array something like this:

    aSystem.Item(1)

    but all I get back is:_

    MagCalculator.P ickList: {MagCalculator. PickList} where

    where MagCalculator is the name of the application.

    How do I read the individual items of the two-dimensional ArrayList?

    2. I want to sort the ArrayList but although there is an abundance of
    information in MSDN on how to sort a one-dimensional ArrayList, there is no
    information on how to sort a two-dimensional ArrayList.

    As mentioned already, I subsequently populate a ComboBox with the two
    dimensional ArrayList, and this seems to work fine except of course the list
    isn't sorted.

    If anyone could point me in the right direction, I'd be grateful.

    Tags: None
    • pamelafluente@libero.it
      #2
      Re: Reading Items in an ArrayList

      Hi Stuat,

      I think you are mislead by the idea that there exists such a thing like

      a "bidimensio nal" arraylist.

      Here an example for your tasks. YOu can change the property being
      compared
      according to your needs.

      -Tommaso




      Public Class Form1
      Inherits System.Windows. Forms.Form



      Private Sub Button1_Click(B yVal sender As System.Object, ByVal e As
      System.EventArg s) Handles Button1.Click

      Dim aSystem As New ArrayList
      aSystem.Add(New PickList(0, "Undefined" ))
      aSystem.Add(New PickList(-1, "Standard UTM"))
      aSystem.Add(New PickList(-2, "UTM-NAD83"))
      aSystem.Add(New PickList(-3, "UTM-NAD27"))

      '1.Get items
      Dim FirstPickList As PickList = DirectCast(aSys tem(0),
      PickList)
      With FirstPickList
      Dim id As String = .ID
      Dim PrimaryKey As Integer = .PrimaryKey
      End With


      '2.Sort Items
      aSystem.Sort(Ne w ComparerForPick List)

      End Sub

      Class ComparerForPick List
      Implements IComparer

      Public Function Compare(ByVal x As Object, ByVal y As Object)
      As Integer Implements System.Collecti ons.IComparer.C ompare

      Dim PickList1 As PickList = DirectCast(x, PickList)
      Dim PickList2 As PickList = DirectCast(y, PickList)

      Return String.Compare( PickList1.ID, PickList2.ID)

      End Function

      End Class

      Public Class PickList

      Private mnPrimaryKey As Integer
      Private msID As String

      Public Sub New(ByVal PrimaryKey As Integer, ByVal ID As String)
      mnPrimaryKey = PrimaryKey
      msID = ID
      End Sub

      Public ReadOnly Property PrimaryKey() As Integer
      Get
      Return mnPrimaryKey
      End Get
      End Property

      Public ReadOnly Property ID() As String
      Get
      Return msID
      End Get
      End Property

      End Class

      End Class







      Stuart ha scritto:
      I am using Visual Basic 2005.
      >
      I have created a two dimensional ArrayList named aSystem that is populated as
      follows:-
      >
      aSystem.Add(New PickList(0, "Undefined" ))
      aSystem.Add(New PickList(-1, "Standard UTM"))
      aSystem.Add(New PickList(-2, "UTM-NAD83"))
      aSystem.Add(New PickList(-3, "UTM-NAD27"))
      >
      and then other items are added to the ArrayList from a sorted recordset as
      follows:-
      >
      Do Until ssTemp.EOF
      aSystem.Add(New PickList(ssTemp .Fields("Primar yKey").Value, _
      ssTemp.Fields(" Name").Value))
      ssTemp.MoveNext ()
      Loop
      >
      The structure of the PickList class is as follows:-
      >
      Public Structure PickList
      >
      Private mnPrimaryKey As Integer
      Private msID As String
      >
      Public Sub New(ByVal PrimaryKey As Integer, ByVal ID As String)
      mnPrimaryKey = PrimaryKey
      msID = ID
      End Sub
      >
      Public ReadOnly Property PrimaryKey() As Integer
      Get
      Return mnPrimaryKey
      End Get
      End Property
      >
      Public ReadOnly Property ID() As String
      Get
      Return msID
      End Get
      End Property
      >
      End Structure
      >
      I use the ArrayList to populate a ComboBox
      >
      With cboSystem
      .DataSource = aSystem
      .ValueMember = "PrimaryKey "
      .DisplayMember = "ID"
      End With
      >
      For the most part everything works fine; the ComboBox is populated with all
      the data.
      >
      I have two problems...
      >
      1. I can't seem to read the items from the ArrayList directly. I would
      expect to be
      able to read the array something like this:
      >
      aSystem.Item(1)
      >
      but all I get back is:_
      >
      MagCalculator.P ickList: {MagCalculator. PickList} where
      >
      where MagCalculator is the name of the application.
      >
      How do I read the individual items of the two-dimensional ArrayList?
      >
      2. I want to sort the ArrayList but although there is an abundance of
      information in MSDN on how to sort a one-dimensional ArrayList, there is no
      information on how to sort a two-dimensional ArrayList.
      >
      As mentioned already, I subsequently populate a ComboBox with the two
      dimensional ArrayList, and this seems to work fine except of course the list
      isn't sorted.
      >
      If anyone could point me in the right direction, I'd be grateful.

        Comment

        • tommaso.gastaldi@uniroma1.it
          #3
          Re: Reading Items in an ArrayList

          Hi Stuart,

          I think you are mislead by the idea that there exists such a thing like

          a "bidimensio nal" arraylist.

          Here an example for your tasks. YOu can change the property being
          compared according to your needs.

          -Tommaso

          Public Class Form1
          Inherits System.Windows. Forms.Form


          Private Sub Button1_Click(B yVal sender As System.Object, ByVal e As

          System.EventArg s) Handles Button1.Click


          Dim aSystem As New ArrayList
          aSystem.Add(New PickList(0, "Undefined" ))
          aSystem.Add(New PickList(-1, "Standard UTM"))
          aSystem.Add(New PickList(-2, "UTM-NAD83"))
          aSystem.Add(New PickList(-3, "UTM-NAD27"))


          '1.Get items
          Dim FirstPickList As PickList = DirectCast(aSys tem(0),
          PickList)
          With FirstPickList
          Dim id As String = .ID
          Dim PrimaryKey As Integer = .PrimaryKey
          End With


          '2.Sort Items
          aSystem.Sort(Ne w ComparerForPick List)


          End Sub


          Class ComparerForPick List
          Implements IComparer

          Public Function Compare(ByVal x As Object, ByVal y As Object)
          As Integer Implements System.Collecti ons.IComparer.C ompare

          Dim PickList1 As PickList = DirectCast(x, PickList)
          Dim PickList2 As PickList = DirectCast(y, PickList)

          Return String.Compare( PickList1.ID, PickList2.ID)

          End Function

          End Class


          Public Class PickList


          Private mnPrimaryKey As Integer
          Private msID As String

          Public Sub New(ByVal PrimaryKey As Integer, ByVal ID As String)

          mnPrimaryKey = PrimaryKey
          msID = ID
          End Sub


          Public ReadOnly Property PrimaryKey() As Integer
          Get
          Return mnPrimaryKey
          End Get
          End Property


          Public ReadOnly Property ID() As String
          Get
          Return msID
          End Get
          End Property


          End Class


          End Class


          Stuart ha scritto:
          I am using Visual Basic 2005.
          >
          I have created a two dimensional ArrayList named aSystem that is populated as
          follows:-
          >
          aSystem.Add(New PickList(0, "Undefined" ))
          aSystem.Add(New PickList(-1, "Standard UTM"))
          aSystem.Add(New PickList(-2, "UTM-NAD83"))
          aSystem.Add(New PickList(-3, "UTM-NAD27"))
          >
          and then other items are added to the ArrayList from a sorted recordset as
          follows:-
          >
          Do Until ssTemp.EOF
          aSystem.Add(New PickList(ssTemp .Fields("Primar yKey").Value, _
          ssTemp.Fields(" Name").Value))
          ssTemp.MoveNext ()
          Loop
          >
          The structure of the PickList class is as follows:-
          >
          Public Structure PickList
          >
          Private mnPrimaryKey As Integer
          Private msID As String
          >
          Public Sub New(ByVal PrimaryKey As Integer, ByVal ID As String)
          mnPrimaryKey = PrimaryKey
          msID = ID
          End Sub
          >
          Public ReadOnly Property PrimaryKey() As Integer
          Get
          Return mnPrimaryKey
          End Get
          End Property
          >
          Public ReadOnly Property ID() As String
          Get
          Return msID
          End Get
          End Property
          >
          End Structure
          >
          I use the ArrayList to populate a ComboBox
          >
          With cboSystem
          .DataSource = aSystem
          .ValueMember = "PrimaryKey "
          .DisplayMember = "ID"
          End With
          >
          For the most part everything works fine; the ComboBox is populated with all
          the data.
          >
          I have two problems...
          >
          1. I can't seem to read the items from the ArrayList directly. I would
          expect to be
          able to read the array something like this:
          >
          aSystem.Item(1)
          >
          but all I get back is:_
          >
          MagCalculator.P ickList: {MagCalculator. PickList} where
          >
          where MagCalculator is the name of the application.
          >
          How do I read the individual items of the two-dimensional ArrayList?
          >
          2. I want to sort the ArrayList but although there is an abundance of
          information in MSDN on how to sort a one-dimensional ArrayList, there is no
          information on how to sort a two-dimensional ArrayList.
          >
          As mentioned already, I subsequently populate a ComboBox with the two
          dimensional ArrayList, and this seems to work fine except of course the list
          isn't sorted.
          >
          If anyone could point me in the right direction, I'd be grateful.

            Comment

            • Stuart
              #4
              Re: Reading Items in an ArrayList

              Thanks Pamela.

              Wow! That was quick!

              ....and it worked. I would never had figured it out myself. You're a star.

              Stuart

              "pamelafluente@ libero.it" wrote:
              Hi Stuat,
              >
              I think you are mislead by the idea that there exists such a thing like
              >
              a "bidimensio nal" arraylist.
              >
              Here an example for your tasks. YOu can change the property being
              compared
              according to your needs.
              >
              -Tommaso
              >
              >
              >
              >
              Public Class Form1
              Inherits System.Windows. Forms.Form
              >
              >
              >
              Private Sub Button1_Click(B yVal sender As System.Object, ByVal e As
              System.EventArg s) Handles Button1.Click
              >
              Dim aSystem As New ArrayList
              aSystem.Add(New PickList(0, "Undefined" ))
              aSystem.Add(New PickList(-1, "Standard UTM"))
              aSystem.Add(New PickList(-2, "UTM-NAD83"))
              aSystem.Add(New PickList(-3, "UTM-NAD27"))
              >
              '1.Get items
              Dim FirstPickList As PickList = DirectCast(aSys tem(0),
              PickList)
              With FirstPickList
              Dim id As String = .ID
              Dim PrimaryKey As Integer = .PrimaryKey
              End With
              >
              >
              '2.Sort Items
              aSystem.Sort(Ne w ComparerForPick List)
              >
              End Sub
              >
              Class ComparerForPick List
              Implements IComparer
              >
              Public Function Compare(ByVal x As Object, ByVal y As Object)
              As Integer Implements System.Collecti ons.IComparer.C ompare
              >
              Dim PickList1 As PickList = DirectCast(x, PickList)
              Dim PickList2 As PickList = DirectCast(y, PickList)
              >
              Return String.Compare( PickList1.ID, PickList2.ID)
              >
              End Function
              >
              End Class
              >
              Public Class PickList
              >
              Private mnPrimaryKey As Integer
              Private msID As String
              >
              Public Sub New(ByVal PrimaryKey As Integer, ByVal ID As String)
              mnPrimaryKey = PrimaryKey
              msID = ID
              End Sub
              >
              Public ReadOnly Property PrimaryKey() As Integer
              Get
              Return mnPrimaryKey
              End Get
              End Property
              >
              Public ReadOnly Property ID() As String
              Get
              Return msID
              End Get
              End Property
              >
              End Class
              >
              End Class
              >
              >
              >
              >
              >
              >
              >
              Stuart ha scritto:
              >
              I am using Visual Basic 2005.

              I have created a two dimensional ArrayList named aSystem that is populated as
              follows:-

              aSystem.Add(New PickList(0, "Undefined" ))
              aSystem.Add(New PickList(-1, "Standard UTM"))
              aSystem.Add(New PickList(-2, "UTM-NAD83"))
              aSystem.Add(New PickList(-3, "UTM-NAD27"))

              and then other items are added to the ArrayList from a sorted recordset as
              follows:-

              Do Until ssTemp.EOF
              aSystem.Add(New PickList(ssTemp .Fields("Primar yKey").Value, _
              ssTemp.Fields(" Name").Value))
              ssTemp.MoveNext ()
              Loop

              The structure of the PickList class is as follows:-

              Public Structure PickList

              Private mnPrimaryKey As Integer
              Private msID As String

              Public Sub New(ByVal PrimaryKey As Integer, ByVal ID As String)
              mnPrimaryKey = PrimaryKey
              msID = ID
              End Sub

              Public ReadOnly Property PrimaryKey() As Integer
              Get
              Return mnPrimaryKey
              End Get
              End Property

              Public ReadOnly Property ID() As String
              Get
              Return msID
              End Get
              End Property

              End Structure

              I use the ArrayList to populate a ComboBox

              With cboSystem
              .DataSource = aSystem
              .ValueMember = "PrimaryKey "
              .DisplayMember = "ID"
              End With

              For the most part everything works fine; the ComboBox is populated with all
              the data.

              I have two problems...

              1. I can't seem to read the items from the ArrayList directly. I would
              expect to be
              able to read the array something like this:

              aSystem.Item(1)

              but all I get back is:_

              MagCalculator.P ickList: {MagCalculator. PickList} where

              where MagCalculator is the name of the application.

              How do I read the individual items of the two-dimensional ArrayList?

              2. I want to sort the ArrayList but although there is an abundance of
              information in MSDN on how to sort a one-dimensional ArrayList, there is no
              information on how to sort a two-dimensional ArrayList.

              As mentioned already, I subsequently populate a ComboBox with the two
              dimensional ArrayList, and this seems to work fine except of course the list
              isn't sorted.

              If anyone could point me in the right direction, I'd be grateful.
              >
              >

                Comment

                Previous template Next
                Working...