Listbox windows form Application

kris

items collection cannot be modified when the datasource property is set listbox c#
I am trying to all items from Listbox1 to Listbox2 but keep getting error, not sure how to fix it.
My code:

using System;
using System.Data;
using System.Data.SqlClient;
using System.Windows.Forms;

namespace SampleApplication{
public partial class Form1 : Form{

public Form1(){
InitializeComponent();
BindValues();
}

private void BindValues(){

string connectionString = @"";
SqlConnection conn = new SqlConnection(connectionString);
SqlCommand cmd = new SqlCommand();
SqlDataAdapter da = new SqlDataAdapter();
DataTable dt = new DataTable();
try
{
conn.Open();
cmd = new SqlCommand("StoredProcedure", conn);
cmd.CommandType = CommandType.StoredProcedure;
da.SelectCommand = cmd;
da.Fill(dt);
listBox1.DataSource = dt;

listBox1.ValueMember = "PO_NUMBER";
listBox1.DisplayMember = "PO Number";

}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
finally
{
cmd.Dispose();
conn.Close();
}
}

private void btnSelect_Click(object sender, EventArgs e){

try
{
if (listBox1.SelectedItem != null)
{
// checking whether listbix1 has items or not if yes then moving items
listBox2.Items.Add(listBox1.SelectedItem.ToString());
listBox1.Items.Remove(listBox1.SelectedItem.ToString());
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
//selecting first item of listbox.

if (listBox1.Items.Count > 0)
listBox1.SelectedIndex = 0;
listBox2.SelectedIndex = listBox2.Items.Count - 1;
}

Thanks

12 Replies

Know the answer? Post it — somebody with the same question will find it here.

Vulpes12y ago
Accepted answer
There must be something wrong somewhere as I just built this simple app and it's working fine - displaying Doe and Smith in the ListBox and then just Smith when the button is pressed:

public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

private void Form1_Load(object sender, EventArgs e)
{
DataTable dt = new DataTable();
dt.Columns.Add("Surname");
dt.Columns.Add("Initial");
dt.Rows.Add("Doe", "J");
dt.Rows.Add("Smith", "S");

foreach(DataRowView drv in dt.DefaultView)
{
listBox1.Items.Add(drv);
}

listBox1.DisplayMember = "Surname";
listBox1.ValueMember = "Initial";
}

private void button1_Click(object sender, EventArgs e)
{
listBox1.Items.RemoveAt(0);
}
}

Just wondering why you set the DataSource property to null originally? Was this set somewhere else?
Vulpes12y ago
I've extended my simple example to show how you can transfer the selected item from listBox1 to listBox2:

public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

private void Form1_Load(object sender, EventArgs e)
{
DataTable dt = new DataTable();
dt.Columns.Add("Surname");
dt.Columns.Add("Initial");
dt.Rows.Add("Doe", "J");
dt.Rows.Add("Smith", "S");

foreach(DataRowView drv in dt.DefaultView)
{
listBox1.Items.Add(drv);
}

listBox1.DisplayMember = "Surname";
listBox1.ValueMember = "Initial";
listBox1.SelectedIndex = 0;

listBox2.DisplayMember = "Surname";
listBox2.ValueMember = "Initial";
}

private void button1_Click(object sender, EventArgs e)
{
if (listBox1.SelectedIndex > -1)
{
listBox2.Items.Add(listBox1.SelectedItem);
listBox1.Items.Remove(listBox1.SelectedItem);
}
}
}
kris12y ago
this works fine for Removing but how to add values from Listbox1 to listbox2 and remove selected value in Listbox1
Munesh Sharma12y ago
see this yr.. http://stackoverflow.com/questions/19576802/transfer-items-from-one-listbox-to-another
kris12y ago
Yes tried that as well, still no luck
Vulpes12y ago
These lines need to be left in:

listBox1.ValueMember = "PO_NUMBER";
listBox1.DisplayMember = "PO Number";
kris12y ago
Nope din't help. Instead of filling with values it's filled with "System.Data.DataRowView
Vulpes12y ago
If you want to remove an item from listBox1, then you'll need to change the underlying datasource and then rebind.

However, rather than do all that, I just wouldn't use data-binding at all - I'd fill the Items collection 'manually'.

To do that remove this line:

listBox1.DataSource = dt;

and replace it with the following:

foreach(DataRowView drv in dt.DefaultView)
{
listBox1.Items.Add(drv);
}
kris12y ago
Yes need to transfer selected value from listbox1 to another
Munesh Sharma12y ago
you want to transfer selected data from list1 to list2.. it is right or not ???
kris12y ago
Removed that as well, but still throws same error
Munesh Sharma12y ago
in your code why are you doing

listBox1.DataSource = null;
after this you are doing this..

listBox1.DataSource = dt;