Hi all,
I have a listbox that is complex bound by an arraylist. The problem is that
when I delete an object from the arraylist, the listbox does not reflect
those changes. I tried refreshing the listbox with no luck and, because it
is already bound, I can't just delete the item directly from the listbox
without an error (because it already has a datasource, you are not allowed
to delete/add anything to the listbox directly).
The application basically is doing nothing but a dual listbox populator
(values in the right listbox are sent to the left with an "add" or an "add
all" button - and vice-versa with "remove" and "Remove all"). Instead of
using datatables, it uses arraylists to keep track of objects. Because the
objects will ultimately contain more than 1 item, I can't do a simple
binding (I wish MS did not ruin the listbox).
If anyone has seen a dual listbox using arraylists (instead of datatables),
please post a link or code .
Private alRegionNames As New ArrayList
Private alSelectedRegionNames As New ArrayList
Private Sub form4_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
loadDBRegionNames()
End Sub
Private Sub loadDBRegionNames()
alRegionNames = SalesRegionsDB.GetRegionNamesActiveAL 'returns an
arraylist of SalesRegionDD objects
lstRegionNames.DisplayMember = "reg_name"
lstRegionNames.ValueMember = "reg_idx"
lstRegionNames.DataSource = alRegionNames 'this listbox is bound to the
arraylist, so changes to the arraylist should reflect in the listbox, but
they do not!
lstSelectedRegionNames.DisplayMember = "reg_name"
lstSelectedRegionNames.ValueMember = "reg_idx"
End Sub
Private Sub Add() 'moves items from the right listbox to the left listbox
If lstRegionNames.SelectedIndex < 0 Then Return
Dim sr As New SalesRegionDD
sr = lstRegionNames.SelectedItem
Me.lstSelectedRegionNames.Items.Add(sr)
Me.TextBox1.Text = sr.reg_idx
Me.alRegionNames.Remove(sr)
End Sub
Private Sub btnAdd_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles btnAdd.Click
Me.Add()
End Sub
Here is the SalesRegionDD class (DD stands for dropdown in case you were
wondering - this is reused in other parts of the app for dropdowns):
Public Class SalesRegionDD
Private _reg_idx As String
Private _reg_name As String
Public Sub New() 'nothing happens here, yet
End Sub
Public Property reg_idx() As String
Get
Return _reg_idx
End Get
Set(ByVal Value As String)
_reg_idx = Value
End Set
End Property
Public Property reg_name() As String
Get
Return _reg_name
End Get
Set(ByVal Value As String)
_reg_name = Value
End Set
End Property
End Class
If anyone has any insight on what I am doing wrong or if this is another MS
DotNet bug I am wasting my time chasing, please let me know. I've spent an
entire week trying to do a simple ping-pong dual listbox (driven by a
database) bound by arraylists.
A dual listbox is such a common item in DB apps, I can't believe that no one
has done one before in VB.Net (I spent an afternoon at the bookstore
looking for an example with no luck).
Help!
TIA
Dave
