473,737 Members | 1,808 Online
Bytes | Software Development & Data Engineering Community
+ Post

Home Posts Topics Members FAQ

listbox bound to arraylist no changing values when values in arraylist are added or deleted

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 alSelectedRegio nNames As New ArrayList

Private Sub form4_Load(ByVa l sender As System.Object, ByVal e As
System.EventArg s) Handles MyBase.Load

loadDBRegionNam es()

End Sub

Private Sub loadDBRegionNam es()

alRegionNames = SalesRegionsDB. GetRegionNamesA ctiveAL '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!

lstSelectedRegi onNames.Display Member = "reg_name"

lstSelectedRegi onNames.ValueMe mber = "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.lstSelectedR egionNames.Item s.Add(sr)

Me.TextBox1.Tex t = sr.reg_idx

Me.alRegionName s.Remove(sr)

End Sub

Private Sub btnAdd_Click(By Val sender As System.Object, ByVal e As
System.EventArg s) 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
Nov 21 '05 #1
0 1688

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

8
2841
by: Vipin Kedia | last post by:
Hi I have written a code for showing the list boxes as selected using a Listitem and the selected property of the items. Now I have 2 list boxes in my page. But it shows only the selected values of the last list box in both the list boxes. If i reverse the calls to the filllistbox methods it shows the value selected for the 1st list box in both the listboxes. I have the code for my method below. Is there a way I can solve this problem?
17
3127
by: amber | last post by:
Hello. Can someone tell me what I may be doing wrong here? I'm using the code (lboxRP is a listbox): Dim newRPindex As Integer newRPindex = Me.lboxRP.FindString(RP) Me.lboxRP.SetSelected(newRPindex, True) When the last line executes, I get an error message:
13
7668
by: Gittyup | last post by:
Help please, We have a form, based on a query, that contains a listbox. The contents of the listbox are based on the results of the query. When the form is opened, the user selects an item from the listbox, and, using the AfterUpdate and Visible properties, a subform appears with information relative to the selected item. It works perfectly.
2
3425
by: Luca | last post by:
Hello, I'm using a windows form in which there is a standard ListBox control. I want to add/remove objects from the ArrayList associated to the ListBox, and I want the ListBox immediately shows graphically the change: e.g. if I remove an element from the ArrayList object, then that element should not be no more displayed in the list box. Actually i'm using this code below:
3
1791
by: Matthew Woods | last post by:
Hi, is there any way to format and order the columns displayed in a datagrid bound to a class that inherits from IBindingList? i have used DataGridTableStyle and added DataGridTextBoxColumns to it in the correct order which works fine if the dataGrid.dataSource = "ArrayList", but it doesn't work for my IBindingList wrapper. If i bind the datasource to the arraylist method then the ListChangedEventHandler is never invoked and my grid only...
0
922
by: Clark Stevens | last post by:
I have an ArrayList (CAL) bound to a listbox (Listbox1). I want to delete an item in the ArrayList and reflect the changes back to the listbox. I have no problem deleting ArrayList items, but how do I get the listbox to reflect the deleted items? Here's what I have so far which doesn't work. What am I doing wrong? Private Sub mnuDelete_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles mnuDelete.Click If...
18
2022
by: Dave Sauny | last post by:
Ok, its a friday, I'm at work and I cant get this to work: I have 3 listboxes on one tab control page. when i select an item in listbox1 i want whatever is selected on the other 2 listboxes unselected. when listbox2 is selected, 1 and 3 should have no items selected and the same with listbox 3. Sounds simple... should be simple! I have tried listbox.clearselected(), listbox.selectedindex=-1 and beating it with a large stick. But so...
7
4532
by: Dave | last post by:
Hi all, After unsuccessfully trying to make my own dual listbox control out of arraylists, I decided to look for a 3rd party control. I've looked for over a week now and can't find anything but ASP.Net stuff when I need a Windows Form control. I've seen dual listbox populators in countless Windows applications, and have seen them run very fast, so I figured this would be extremely popular. Here's how it should work:
4
4963
by: rn5a | last post by:
Can the items in a ListBox be sorted by the name of the items? The ListBox actually lists all directories & files existing in a directory on the server. Note that all the directories should be listed first followed by the files.
0
8786
by: Hystou | last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it. First, let's disable language synchronization. With a Microsoft account, language settings sync across devices. To prevent any complications,...
0
9467
Oralloy
by: Oralloy | last post by:
Hello folks, I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>". The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed. This is as boiled down as I can make it. Here is my compilation command: g++-12 -std=c++20 -Wnarrowing bit_field.cpp Here is the code in...
0
9331
jinu1996
by: jinu1996 | last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth. The Art of Business Website Design Your website is...
1
9257
by: Hystou | last post by:
Overview: Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For most users, this new feature is actually very convenient. If you want to control the update process,...
0
9204
tracyyun
by: tracyyun | last post by:
Dear forum friends, With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each protocol has its own unique characteristics and advantages, but as a user who is planning to build a smart home system, I am a bit confused by the choice of these technologies. I'm particularly interested in Zigbee because I've heard it does some...
0
8203
agi2029
by: agi2029 | last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing, and deployment—without human intervention. Imagine an AI that can take a project description, break it down, write the code, debug it, and then launch it, all on its own.... Now, this would greatly impact the work of software developers. The idea...
0
6052
by: conductexam | last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one. At the time of converting from word file to html my equations which are in the word document file was convert into image. Globals.ThisAddIn.Application.ActiveDocument.Select();...
0
4823
by: adsilva | last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
2
2744
muto222
by: muto222 | last post by:
How can i add a mobile payment intergratation into php mysql website.

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.