apply alternative style for gridview merge rows

Hello..

can anyone help me to apply alternative style for gridview merge rows..TQ.

Below is my Javascript and my aspx.cs code

private void MergeGridviewRows(GridView gridView)
{
for (int rowIndex = gridView.Rows.Count - 2; rowIndex >= 0; rowIndex--)
{
GridViewRow row = gridView.Rows[rowIndex];
GridViewRow previousRow = gridView.Rows[rowIndex + 1];
if (row.Cells[0].Text == previousRow.Cells[0].Text && row.Cells[1].Text == previousRow.Cells[1].Text)
{
row.Cells[0].RowSpan = previousRow.Cells[0].RowSpan < 2 ? 2 : previousRow.Cells[0].RowSpan + 1;
row.Cells[1].RowSpan = previousRow.Cells[1].RowSpan < 2 ? 2 : previousRow.Cells[1].RowSpan + 1;
previousRow.Cells[0].Visible = false;
previousRow.Cells[1].Visible = false;
}
if (row.Cells[2].Text == previousRow.Cells[2].Text && row.Cells[3].Text == previousRow.Cells[3].Text)
{
row.Cells[2].RowSpan = previousRow.Cells[2].RowSpan < 2 ? 2 : previousRow.Cells[2].RowSpan + 1;
row.Cells[3].RowSpan = previousRow.Cells[3].RowSpan < 2 ? 2 : previousRow.Cells[3].RowSpan + 1;
previousRow.Cells[2].Visible = false;
previousRow.Cells[3].Visible = false;
}
if (row.Cells[4].Text == previousRow.Cells[4].Text && row.Cells[5].Text == previousRow.Cells[5].Text)
{
row.Cells[4].RowSpan = previousRow.Cells[4].RowSpan < 2 ? 2 : previousRow.Cells[4].RowSpan + 1;
row.Cells[5].RowSpan = previousRow.Cells[5].RowSpan < 2 ? 2 : previousRow.Cells[5].RowSpan + 1;
previousRow.Cells[4].Visible = false;
previousRow.Cells[5].Visible = false;
}
}
}
protected void gvUpdateDate_PreRender(object sender, EventArgs e)
{
MergeGridviewRows(gvUpdateDate);
}