How do I loop through items in a list box and then remove those item?

Question

I'm getting the error below when trying to loop through a listbox and then remove the item.

List that this enumerator is bound to has been modified. An enumerator can only be used if the list does not change.

foreach (string s in listBox1.Items)
{
    MessageBox.Show(s);
    //do stuff with (s);
    listBox1.Items.Remove(s);
}

How can I remove the item and still loop through the contents?

Answer 1

Do you want to remove all items? If so, do the foreach first, then just use Items.Clear() to remove all of them afterwards.

Otherwise, perhaps loop backwards by indexer:

listBox1.BeginUpdate();
try {
  for(int i = listBox1.Items.Count - 1; i >= 0 ; i--) {
    // do with listBox1.Items[i]

    listBox1.Items.RemoveAt(i);
  }
} finally {
  listBox1.EndUpdate();
}