Listbox Control

Hi All,

I have populated a listbox control with some items and I then want to remove those selected by the user:

Code:

---

          foreach (ListItem li in ContactList.Items)
            {
                if (li.Selected == true)
                {
                    ContactList.Items.Remove(li.Text);
                }
            }

---

trouble is as soon as the first item is removed code crashes because the foreach is now out of sync.

HOw can I force only those items selected to be removed

The usual way to do this is to loop through the items in reverse - that way the removals do not affect the part of the collection which you still have to go through.

a ListBox has a SelectedItems property, use that and then remove each item in that collection.

Theres no SeletedItems Property only SelectedItem. I'll have a go with the reverse loop.

Yes there is

It's not such a smart idea to change the size of list of items, during running on it in a for/foreach loop.
You could use the while loop instead:

Code:

---

int i = 0;
while(i < contactList.Items.Count)
{
  if(contactList.Items[i].Selected)
      contactList.Items.RemoveAt(i);
  else
      i++;
}

---

Alternatively:

Code:

---

for(int i=contactList.Items.Count-1; i>=0; i--)
{
    if(needToBeRemoved...)
        contactList.Items.RemoveAt(i);
}

---

BigEd, No there's not. It might be that because I'm using a Web Listbox that it's not there.

Code:

---

<asp:ListBox .....

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Sorry guy's I forgot to say if it was windows or web.

Quote:

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Originally Posted by Bill Crawley

BigEd, No there's not. It might be that because I'm using a Web Listbox that it's not there.

Code:

---

<asp:ListBox .....

---

Sorry guy's I forgot to say if it was windows or web.

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Yes, that would be why. A standard WinForms ListBox has that property.