SuperGridControl After the exchanged Why DataSource sort not change?

Question

I want to Exchange SuperGridControl DataItem,But after the exchanged Source not Change,This is My Code:

Section 1, GridRow move to next row code :

        GridItemsCollection gridRows = sgcData.PrimaryGrid.Rows;
        GridRow activeRow = sgcData.PrimaryGrid.ActiveRow as GridRow; 
        if (gridRows == null || activeRow.Index == gridRows.Count - 1) return;
        GridRow nextGridRow = gridRows[activeRow.Index + 1] as GridRow; 
        sgcData.PrimaryGrid.Rows[activeRow.Index] = nextGridRow;
        sgcData.PrimaryGrid.Rows[nextGridRow.Index] = activeRow;
        sgcData.PrimaryGrid.SetActiveRow(activeRow); 

Section 2, GridRow move to previous row code :

        GridItemsCollection gridRows = sgcData.PrimaryGrid.Rows; 
        GridRow activeRow = sgcData.PrimaryGrid.ActiveRow as GridRow; 
        if (gridRows == null || activeRow.Index == 0) return; 
        GridRow previousGridRow = gridRows[activeRow.Index - 1] as GridRow; 
        sgcData.PrimaryGrid.Rows[previousGridRow.Index] = activeRow; 
        sgcData.PrimaryGrid.Rows[activeRow.Index] = previousGridRow; 
        sgcData.PrimaryGrid.SetActiveRow(activeRow);

Finally, After the exchanged Why source not change ?