How to Merge GridView Rows (Cells with Equal Values)

How to Merge GridView Rows (Cells with Equal Values)

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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);

}