protected virtual void OnBeforeSearching(BeforeSearchingEventArgs e) {
     if (this.BeforeSearching != null)
         this.BeforeSearching(this, e);
 }
        /// <summary>
        /// Handle the SearchForVirtualList event, which is called when the user types into a virtual list
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        protected virtual void HandleSearchForVirtualItem(object sender, SearchForVirtualItemEventArgs e) {
            // The event has e.IsPrefixSearch, but as far as I can tell, this is always false (maybe that's different under Vista)
            // So we ignore IsPrefixSearch and IsTextSearch and always to a case insensitve prefix match.

            // We can't do anything if we don't have a data source
            if (this.DataSource == null)
                return;

            // Where should we start searching? If the last row is focused, the SearchForVirtualItemEvent starts searching
            // from the next row, which is actually an invalidate index -- so we make sure we never go past the last object.
            int start = Math.Min(e.StartIndex, this.DataSource.GetObjectCount() - 1);

            // Give the world a chance to fiddle with or completely avoid the searching process
            BeforeSearchingEventArgs args = new BeforeSearchingEventArgs(e.Text, start);
            this.OnBeforeSearching(args);
            if (args.Canceled)
                return;

            // Do the search
            int i = this.FindMatchingRow(args.StringToFind, args.StartSearchFrom, e.Direction);

            // Tell the world that a search has occurred
            AfterSearchingEventArgs args2 = new AfterSearchingEventArgs(args.StringToFind, i);
            this.OnAfterSearching(args2);

            // If we found a match, tell the event
            if (i != -1)
                e.Index = i;
        }