void AddItem(object sender, EventArgs e)
        {
            IViewItem _viewItem = new ItemForm();

            _viewItem.ItemCreated += delegate(RadioComponent rc)
            {
                int maxKey = Items.Keys.Count() != 0 ? Items.Keys.Max() : 0;
                try
                {
                    _manager.AddNode(rc, _view.SelectedCategoryName, ++maxKey);
                    Items.Add(maxKey, rc);
                    _view.UpdateItems(Items);
                }
                catch (Exception ex)
                {
                    _messageService.ShowError(ex.Message);
                }
            };

            _viewItem.Show();
        }