Telerik RADGrid and sorting

I'm using the RADGridView for WPF to display some data. It is pulled dynamically from DB so I don't know column names or the type of data contained in each cell. I want to let the user sort the data on each column when it double-clicks on a column header.

For some reason the grid doesn't sort. This is what I have so far.

private void SetEventHandlers()
        {
            if (_grid != null)
            {
                _grid.AddHandler(GridViewCellBase.CellDoubleClickEvent, new EventHandler<RadRoutedEventArgs>(OnCellDoubleClick), true);

            }
        }


private void OnCellDoubleClick(object sender, RoutedEventArgs e)
        {
            GridViewCellBase cell = e.OriginalSource as GridViewCellBase;
            if (cell != null && cell is GridViewHeaderCell)
            {
                SetSorting(cell);
            }
        }



private void SetSorting(GridViewCellBase cell)
        {
            GridViewColumn column = cell.Column;
 开发者_JAVA技巧           SortingState nextState = GetNextSortingState(column.SortingState);
            _grid.SortDescriptors.Clear();
            if (nextState == SortingState.None)
            {
                column.SortingState = SortingState.None;
            }
            else
            {
                _grid.SortDescriptors.Add(CreateColumnDescriptor(column, nextState));
                column.SortingState = nextState;
            }

        }

EDIT:

private ColumnSortDescriptor CreateColumnDescriptor(GridViewColumn column, SortingState sortingState)
        {
            ColumnSortDescriptor descriptor = new ColumnSortDescriptor();
            descriptor.Column = column;
            if (sortingState == SortingState.Ascending)
            {
                descriptor.SortDirection = ListSortDirection.Ascending;
            }
            else
            {
                descriptor.SortDirection = ListSortDirection.Descending;
            }


            return descriptor;
        }

It turned out than my RadGrid data was binded to an ObservableCollection. Sorting functionality of the grid itself did not work. Sorting the ObservableCollection was the solution. I ended up sorting the ObservableCollection using linq.