protected virtual void OnItemStateChanged(ItemStateChangedEventArgs e)
 {
     if (ItemStateChanged != null)
     {
         ItemStateChanged(this, e);
     }
 }
        private bool DoItemStateChanged(ItemEventType ev, ListViewItem item, int index)
        {
            ItemStateChangedEventArgs e = new ItemStateChangedEventArgs(ev, item, index);

            OnItemStateChanged(e);
            return(e.Proceed);
        }