MARKUS

        ListBox _dragSource = null;

        private void lstSymbolPrivate_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)

        {

            _dragSource = sender as ListBox;

            object item = Symbol.GetDataFromListBox(sender as ListBox, e.GetPosition(sender as ListBox));

            if (item != null)

            {

                string _data = string.Empty;

                using (KCOMEntities Entity = new KCOMEntities(ConnectStringBuilder.KCOMConnectionString().ToString()))

                {

                    string id = (item as Symbol_Custom).ID;

                    if (RadTab.SelectedIndex == 0)

                        _data = Entity.SYMBOL_PRIVATE.Where(data => data.ID == id).FirstOrDefault().DATA;

                    else

                        _data = Entity.SYMBOL_PUBLIC.Where(data => data.ID == id).FirstOrDefault().DATA;

                }

                DragDrop.DoDragDrop(_dragSource, _data, DragDropEffects.Copy);

            }

        }

        /// <summary>

        /// get data from list box where user clicked

        /// </summary>

        /// <author>humkyung</author>

        /// <date>2018.05.30</date>

        /// <param name="source"></param>

        /// <param name="point"></param>

        /// <returns></returns>

        private static object GetDataFromListBox(ListBox source, Point point)

        {

            UIElement element = source.InputHitTest(point) as UIElement;

            if (element != null)

            {

                object data = DependencyProperty.UnsetValue;

                while (data == DependencyProperty.UnsetValue)

                {

                    data = source.ItemContainerGenerator.ItemFromContainer(element);

                    if (data == DependencyProperty.UnsetValue)

                    {

                        element = VisualTreeHelper.GetParent(element) as UIElement;

                    }

                    if (element == source)

                    {

                        return null;

                    }

                }

                if (data != DependencyProperty.UnsetValue)

                {

                    return data;

                }

            }

            return null;

        }