How to Merge GridView Rows (Cells with Equal Values)

There are a lot of methods in the Internet solving the problem of how to merge GridView rows if neighbour cells show equal values. My approach is not the first; however, I think, it is rather universal and very short - less than 20 lines of code.

The algorithm is simple: to bypass all the rows, starting from the second at the bottom, to the top. If a cell value is the same as a value in the previous (lower) row then to increase RowSpan and to make invisible the lower cell, and so forth.

The code that merges cells is very short:

 public class GridDecorator

    {

        public static void MergeRows(GridView gridView)

        {

            for (int rowIndex = gridView.Rows.Count - 2; rowIndex >= 0; rowIndex--)

            {

                GridViewRow row = gridView.Rows[rowIndex];

                GridViewRow previousRow = gridView.Rows[rowIndex + 1];

                for (int i = 0; i < row.Cells.Count; i++)

                {

                    if (row.Cells[i].Text == previousRow.Cells[i].Text)

                    {

                        row.Cells[i].RowSpan = previousRow.Cells[i].RowSpan < 2 ? 2 :       previousRow.Cells[i].RowSpan + 1;

                        previousRow.Cells[i].Visible = false;

                    }

                }

            }

        }

    }

The last action is to add an OnPreRender event handler for the GridView:

protected void gridView_PreRender(object sender, EventArgs e)

    {

        GridDecorator.MergeRows(gridView);

    }