Collection was modified; enumeration may not execute error when removing a ListItem from a LIstBox

Question

I have two ListBoxes, lstAvailableColors and lstSelectedColors. Between each listbox are two buttons, Add and Remove. When a color or colors is selected in lstAvailableCol

Answer 1

The problem you face is that you can't modify the collection you itterate thru. You could solve this by using a single linq:

protected void btnAdd_Click(object sender, EventArgs e)
{
    lstAvailableColors.Items.RemoveAll(ac => ac.Selected);
}