drag column to group

        private void svc_PreviewDragOver(object sender, RadDragOverEventArgs e)
        {
            if (e.DragInstance is GridDataRowElement)
            {
                Console.WriteLine(e.HitTarget);
                e.CanDrop = e.HitTarget is GridDataRowElement ||
                            e.HitTarget is GridTableElement ||
                            e.HitTarget is GridSummaryRowElement ||
                            e.HitTarget is GroupPanelElement;
            }
        }

        private void svc_PreviewDragDrop(object sender, RadDropEventArgs e)
        {
            var rowElement = e.DragInstance as GridDataRowElement;
            if (rowElement == null)
            {
                return;
            }
            if (e.HitTarget is GroupPanelElement)
            {
                e.Handled = false;
            }
            else
            {
                e.Handled = true;

                var dropTarget = e.HitTarget as RadItem;
                var targetGrid = dropTarget.ElementTree.Control as RadGridView;
                if (targetGrid == null)
                {
                    return;
                }

                var dragGrid = rowElement.ElementTree.Control as RadGridView;
                if (targetGrid != dragGrid)
                {
                    e.Handled = true;
                    //append dragged rows to the end of the target grid
                    int index = targetGrid.RowCount;

                    //Grab every selected row from the source grid, including the current row
                    List<GridViewRowInfo> rows =
                        dragGrid.SelectedRows.ToList<GridViewRowInfo>();
                    if (dragGrid.CurrentRow != null)
                    {
                        GridViewRowInfo row = dragGrid.CurrentRow;
                        if (!rows.Contains(row))
                            rows.Add(row);
                    }
                    this.MoveRows(targetGrid, dragGrid, rows, index);
                }
            }
        }