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

As the other answer mentioned, you can't remove items until you've completed the iteration. So perhaps something like this will be cleanest for you:

var itemsToRemove =
lstAvailableColors.Items.Cast().Where(i => i.IsSelected).ToArray();

foreach(ListItem item in itemsToRemove) lstAvailableColors.Remove(item);