C# removing items from listbox

Question

I have a listbox being populated from a SQLDATA pull, and it pulls down some columns that i dont want like OBJECT_dfj, OBJECT_daskd. The key is all of these being with OBJE

Answer 1

   for (int i = 0; i < listBox1.Items.Count; i++)
    {
        if (textBox1.Text == listBox1.Items[i].ToString())
        {
            jeElement = true;
            break;
        }
    }
    if (jeElement)
    {
        label1.Text = "je element";
    }
    else
    {
        label1.Text = "ni element";
    }
    textBox1.ResetText();
    textBox1.Focus();

}

private void Form1_KeyDown(object sender, KeyEventArgs e)
{
    if (e.Alt == true && e.KeyCode == Keys.A)
    {
        buttonCheck.PerformClick();
    }
}

}

Answer 2

You can use following code too:

 foreach (var item in listBox1.Items.Cast<string>().ToList())
 {
     string removelistitem = "OBJECT";
     if (item.Contains(removelistitem))
     {
        listBox1.Items.Remove(item);
     }
 }

Answer 3

protected void lbAddtoDestination_Click(object sender, EventArgs e)
        {
            AddRemoveItemsListBox(lstSourceSkills, lstDestinationSkills);
        }
        protected void lbRemovefromDestination_Click(object sender, EventArgs e)
        {
            AddRemoveItemsListBox(lstDestinationSkills, lstSourceSkills);
        }
        private void AddRemoveItemsListBox(ListBox source, ListBox destination)
        {
            List<ListItem> toBeRemoved = new List<ListItem>();
            foreach (ListItem item in source.Items)
            {
                if (item.Selected)
                {
                    toBeRemoved.Add(item);
                    destination.Items.Add(item);
                }
            }
            foreach (ListItem item in toBeRemoved) source.Items.Remove(item);
        }

Answer 4

You can't modify the references in an enumerator whilst you enumerate over it; you must keep track of the ones to remove then remove them.

This is an example of the work around:

List<string> listbox = new List<string>();
List<object> toRemove = new List<object>();

foreach (string item in listbox)
{
    string removelistitem = "OBJECT";
    if (item.Contains(removelistitem))
    {
        toRemove.Add(item);
    }
}

foreach (string item in toRemove)
{
    listbox.Remove(item);
}

But if you're using c#3.5, you could say something like this.

listbox.Items = listbox.Items.Select(n => !n.Contains("OBJECT"));

Answer 5

You can do it in 1 line, by using Linq

listBox1.Cast<ListItem>().Where(p=>p.Text.Contains("OBJECT")).ToList().ForEach(listBox1.Items.Remove);

Answer 6

You could try this method:

List<string> temp = new List<string>();

    foreach (string item in listBox1.Items)
    {
        string removelistitem = "OBJECT";
        if(item.Contains(removelistitem))
        {
            temp.Items.Add(item);
         }
     }

    foreach(string item in temp)
    {
       listBox1.Items.Remove(item);
    }

This should be correct as it simply copies the contents to a temporary list which is then used to delete it from the ListBox.

Everyone else please feel free to mention corrections as i'm not 100% sure it's completely correct, i used it a long time ago.